RU2817861C1 - System for automatic detection of overheating of electrical equipment elements, which includes several sensors, method of its use and testing - Google Patents

Abstract

FIELD: control and measuring equipment.

SUBSTANCE: invention relates to automatic detection of overheating of electrical equipment elements. To this end, the system includes: at least two gas sensors (S1, S2) intended for installation in at least two different monitored zones for detecting gases released when the monitored element is heated, or thermally activated gas-releasing materials installed on it; controller configured to be connected to at least two gas sensors S1 and S2 and generate a notice of overheating and/or transmit information on such overheating to another device, when the sensor S1 detects gases released during heating of the monitored element in one monitored zone or thermally activated gas-releasing materials installed on it, taking into account the concentration of background gases, occurrence of which is not associated with heating of controlled elements, in air, detected by sensor S2, installed in another controlled area.

EFFECT: improving reliability and safety of electrical equipment operation due to timely detection of defects accompanied by overheating of electrical equipment elements.

26 cl, 6 dwg, 4 tbl

Description

Field of technology to which the claimed group of inventions relates

The group of inventions relates to systems for detecting emergency and pre-fire situations, namely to systems for automatically detecting overheating of electrical equipment elements, methods of their use and testing.

State of the art

According to statistics, faulty electrical equipment is the cause of 30% of fires. Often such fires occur due to excessive heating of conductive elements, contact connections and insulation. Timely detection of electrical equipment defects accompanied by overheating makes it possible to eliminate faults before fires occur and thereby reduce the number of fires and technological violations. To detect overheating of electrical equipment elements, many methods have been developed that can be classified as direct (measuring the temperature of controlled equipment using temperature sensors), as well as indirect (measuring other parameters that change due to temperature increases). One example of an indirect method for determining overheating is the gas analytical method, the essence of which is the detection by gas sensors of substances released when the controlled elements overheat due to thermal destruction or fire.

The gas analytical method uses semiconductor, thermocatalytic, conductometric, electrochemical or optical sensors with different principles of operation, but serving the same purpose - identifying products in the gas phase that indicate the presence of overheating.

The source [RU 2022250, publication date 10.30.1994] describes a device and method for informing about a pre-fire situation, based on the determination of thermal destruction products of various substances using infrared spectroscopy in three wavelength ranges, which are characterized by the absorption of hydrocarbon, chlorine-containing and oxygen-containing radicals and molecules , formed as a result of thermal decomposition or ignition of electrical insulating materials. Increased reliability of the device is achieved by subtracting signals corresponding to the permissible concentration of radicals from the simultaneously recorded values of the intensity of radiation passing through the analyzed gas-air mixture, and comparing this difference with a threshold value. A feature of the proposed device and method is that ensuring high accuracy and efficiency in determining the concentration of hydrocarbon, chlorine-containing and oxygen-containing radicals can only be achieved in closed premises of various classes and purposes: nuclear power plants, manned deep-sea vehicles, ship premises, coal mines, space and aircraft compartments devices, granaries, warehouses, etc., since when using the described invention in open rooms or in the open air, infrared sensors can also detect foreign gaseous substances that absorb in the same spectral ranges to which the sensors of the described invention are tuned. In addition, the device detects gases released when a flame occurs, i.e. An alarm notification is generated after a fire.

The method for detecting a pre-fire situation and preventing a fire, described in the source [SU 1277159 A1, publication date 12/15/1986], is based on measuring the intensity of monochromatic radiation that changes upon absorption at a frequency corresponding to gaseous products of thermal destruction. When the threshold values are exceeded, the fire alarm control signal is triggered. This method is characterized by low reliability and a high probability of false positives. In addition, the method allows you to record only actively developing thermal destruction processes close to the moment of ignition, since the control signal is generated only on the basis of the signal exceeding a threshold value without taking into account the rate of increase in concentration, and also without taking into account the background concentration of the analyzed gases in the environment.

To reduce the number of false alarms that occur as a result of detection of third-party gases by sensors, as well as to identify facts of overheating of the controlled elements before thermal destruction begins, special thermally activated materials (stickers) are used, which are installed on the controlled elements. When heated above a predetermined threshold temperature, such stickers release signal gases that are detected by sensors. Thus, the source [JP 666648, publication date 03/11/1994] discloses a device for early detection of overheating in hard-to-reach places of electrical and mechanical equipment, consisting of an odorant encapsulated in a hot-melt composition and a sensor that detects the signal odorant. In this case, a hot-melt composition with an odorant is placed next to the controlled object. Alternative embodiments of the invention include hot-melt microcapsules filled with odorant, as well as odorants mixed with fatty acids such as waxes. The hot melt composition can be applied to sheet material with an adhesive layer to form a heat-sensitive stacker, or mixed with an adhesive agent to form an odor-releasing paint. A feature of this invention is the use of hot-melt polymers, which, when heated to a softening or melting temperature, can melt, drain from the controlled element or form a foam layer. Despite the fact that such systems are configured to register substances that are not contained in indoor air under normal operating conditions, they are nevertheless not immune from false alarms, since the sensors can detect foreign substances from the ambient air that are similar in their optical or other properties to the detected gases.

A system for detecting local overheating of electrical equipment is also known from the prior art, which discloses the use of a microporous polymer composite material capable of releasing pore contents in the mode of multiple heating and cooling cycles [RU 2596953, publication date 09.10.2016]. The described system consists of a gas sensor connected to a recorder, which is connected to a signal supply system, and a polymer composite material applied to areas of the electrical circuit that are prone to heating and having an opening temperature in the range of 80-200°C. Despite the fact that special marker gases are used as the contents of the pores of the polymer composite material of the device according to this document, nevertheless, the sensor of the device can respond to the presence in the environment of third-party gases that are similar in spectral properties to the low-boiling substances used. In addition, systems based on the use of heat-sensitive gas-emitting stickers are able to control overheating only in the area of electrical equipment on which the stickers are installed.

It should be noted that the systems described above, based both on the use of gas-emitting stickers and the detection of gases released during the thermolysis of insulating materials, include single sensors, which are not enough to monitor the condition of large equipment, objects consisting of several isolated from each other sections, large equipment, etc. The prior art knows systems that detect overheating using the gas analytical method, which include several sensors installed in different parts of the controlled objects, or configured to take air samples from various sections isolated from each other, with subsequent measurement of the concentration of certain signal gases. This scheme allows not only to quickly detect the occurrence of dangerous heating, but also to accurately determine the location of an accident or fire and timely take measures to minimize the consequences.

For example, the source [US 2021/0299498 A1, publication date 01/20/2021] describes a system for extinguishing a fire in a room, in which several stationary fire extinguishing devices are responsible for suppressing a fire in a separate area of the room, and accurately identifying the zone in which the fire occurred occurs using a matrix sensor with many pixels sensitive to electromagnetic radiation, with each pixel covering a specific area of the controlled room. When a fire zone is determined by the number of pixels that have registered an electromagnetic disturbance, the fire extinguishing devices corresponding to this zone are activated. The described system can be easily scaled to protect large rooms or rooms with complex geometry. In addition, it is easy to program and quick to install and operate. Each pixel can be individually adjusted to the threshold of electromagnetic radiation emitted by stationary heat sources, which prevents false alarms associated with the capture of heat generated by these sources. However, whenever these stationary sources are moved, dismantled, or installed, the matrix sensor must be reprogrammed. In addition, such a system does not have high reliability, since a gradual increase in the temperature of the controlled object, not associated with emergency situations, can also lead to false operation of the system. The described system cannot be used on industrial facilities and equipment operating at high operating temperatures, the value of which is close to the threshold.

A method and device for detecting a fire in one or more controlled zones using a system of suction piping connecting multiple controlled zones using air intake openings is described in the source [EP 2004/009450, publication date 04.24.2004] and allows the location of the fire to be determined with high accuracy fire by connecting multiple suction pipes monitoring specific areas to one sensor. A similar principle of operation is also disclosed in the source [US 11189143, publication date November 30, 2021], which discloses an aspiration smoke detection system for detecting a fire and its location, including a unit for detecting airborne smoke particles, as well as one or more local sensors, located remotely from the smoke detection unit to measure the properties of air from the area of interest that is drawn into the smoke detection system during aspiration. To more accurately determine the location of a fire and reduce the number of false alarms, an aspiration detector system was developed [EP 2881922, publication date 06/10/2015], containing a double network for supplying analyzed air, one of which operates and detects the state of the environment continuously, and the other starts only in if the first system detects signs of fire. In this case, the second system is activated only in those zones in which the first system has detected deviations from normal values, with a certain delay, taking into account the speed of passage of the intake air to the detector. An alarm is generated only if the detector of the second system confirms the data received from the first system.

Despite the fact that such systems make it possible not only to determine the occurrence of a pre-fire situation, but also to identify with high accuracy and reliability its exact location even in large areas, as well as several unconnected rooms, their feature is the delay between the moment of air suction and its analysis by the detector, due to the distance of the detector from the air intake openings. In addition, such systems are also prone to detecting foreign gases that have arisen in the air of controlled premises not as a result of a fire hazardous situation, but due to other reasons, which can lead to false alarms even in the presence of a parallel confirmatory aspiration system described in the source [EP 2881922]. Another feature of such systems is the complexity of their installation and the impossibility of using individual elements of small electrical equipment to monitor heating-related defects, as well as the low sensitivity of the detectors.

A method and device for detecting and determining the location of ignition in one or more controlled areas are described in the source [RU 2342709 C2, publication date 11/10/2007]. The suction piping system, by means of an air intake device, supplies air samples from each individual controlled zone to the sensor for detecting at least one combustion product in the selected air samples. In this case, after receiving a positive result from at least one air sample, the air intake device analyzes a repeat sample taken from the same area. By analyzing the concentrations in two consecutive air samples obtained from the same zone, a conclusion is made about the location of the ignition, as well as the degree of its development.

The difference in readings obtained sequentially from one sensor makes it possible to predict the development of a fire hazardous situation and launch the appropriate fire protection mechanisms when using the utility model [RU 84717 U1, publication date 07.20.2009]. A similar purpose is served by the invention [RU 2596063 C1, publication date 08/27/2016], which describes a method for pre-accident, emergency and post-accident control of hazard sources in sealed inhabited objects, in particular submarines, based on dividing the controlled object into signal zones, each which are controlled by a set of sensors, including those that control the release of highly dispersed aerosols formed as a result of heating of various polymer materials, electrical components and elements, determining the parameters of signal zones under various operating modes, as well as recording the excess of established values in the event of an emergency. At the same time, the control system, which receives signals from sensors, compares the readings received from neighboring sensors to carry out physical and mathematical modeling of accident development processes and prompt decision-making to eliminate an emergency situation and its consequences.

However, the above systems cannot be used to monitor the condition of open objects or large areas, since they are designed to ensure the explosion and fire safety of closed volumes. When using such devices and systems at large industrial enterprises or large installations, especially those located outdoors, the risk of false alarms increases due to the detection of gases and aerosols that have a different source of origin and fall into the control zone of the sensors of the described systems as a result of diffusion.

There are known devices for measuring the composition of a gaseous medium [RU 111675 U1, publication date 12/20/2011; RU 159702 U1, date of publication 02.20.2016], containing gas sensors, an analog measuring part, a transceiver, a microprocessor module, a power supply circuit for the sensor device and the device as a whole, which can be used, for example, as autonomous wireless pre-fire detectors or toxic gas sensors. In particular, the sensors are configured to detect the concentration of methane or carbon monoxide in the air. The proposed devices solve the problem of complete energy independence from mains power and increasing battery life.

The document [RU 2175779, publication date November 10, 2001] describes a method for diagnosing a pre-fire situation and preventing a fire by monitoring the values of informative parameters characterizing the state of air at a protected facility. The technical result is to simplify the method and provide early detection of fire by measuring the concentration of gaseous products of thermal destruction as informative parameters: CO, CO ₂ , NOx HCl, H ₂ , CH ₄ , NH ₃ , O ₂ , Cl ₂ , H ₂ S, SO ₂ , НСО, C ₆ H ₅ OH - and other reducing and oxidizing gases, as well as the concentration of suspended particles in the air and its temperature. Moreover, for each dependence of informative parameters on time, at least one value of the derivative is determined in the time interval of 0.1-60 s. Based on the results of processing these parameters, the occurrence of a pre-fire situation is judged.

The device described in the source [RU 95849, publication date 07/10/2010] is based on a similar mechanism of action, which determines the parameters of the gas environment, including the content of CO and H ₂ , which allows the device to be used as a fire detector. The invention consists of gas sensors, the operating modes of which are controlled by a microprocessor module, an analog measuring part, a module for processing and storing measurements, as well as power supplies for the device. The hardware-software interface is integrated into the electronic circuit of the device for transmitting data and commands over wireless networks, and during the calibration interval the device can operate autonomously and uninterruptedly without replacing power supplies, thanks to the optimization of the measurement and data transmission algorithm.

To increase the reliability of operation, the devices described above may contain several identical sensors or sensors of different types, designed to confirm the alarm signal received from one of the sensors. Also, the above devices are characterized by high sensitivity to detected gases and high reliability, since the fire hazard is assessed by the concentrations of several controlled gas components. However, a common feature of these devices is the detection of the first signs of combustion, rather than excessive heating. The reason for this is the high threshold concentrations of thermolysis products, corresponding to the intensive development of the defect (combustion). A decrease in threshold concentrations leads to multiple false alarms due to the presence in the ambient air of gases similar in their parameters to thermal destruction products. In other words, the sensors of the described devices can with a high probability capture foreign gases from the environment whose spectral or other properties are close to the marker substances used. False alarms are typical when operating such systems in chemical plants, where emissions of various chemicals may occur, as well as near industrial enterprises and production and transport infrastructure.

As a prototype, a device for detecting fire in electrical products was selected, which includes a system of suction pipes that communicates with the product being monitored through at least one suction hole and through which a representative air sample is taken; an early fire detection module having one or more sensors for detecting at least one substance in the sampled air indicative of ignition; a controller for providing an early fire detection signal in response to a result detected by the at least one detection unit [US 7796047, publication date 05/10/2007]. In this case, the early fire detection module is made in the form of a rack for installation in a controlled product, and the system of suction pipes communicates with individual racks of electrical equipment to be controlled using at least one corresponding suction hole, through which representative air samples are taken, analyzed in the system early fire detection. The distinctive features of the above invention are its large dimensions, the complexity of installation, the impossibility of its use for electrical installations of non-standard shapes and sizes, as well as the low sensitivity of the method and the high probability of false positives due to the reasons given above.

Timely and accurate detection of emergency defects, accompanied by excessive heating up to the point of fire or smoldering, is an important task to ensure the safe operation of various equipment, including electrical equipment. Despite the existing variety of systems and methods for detecting pre-fire and emergency situations, their common drawback, which limits their widespread use, is the high probability of false alarms when foreign gases, similar in structure to the gases released when heating elements of electrical equipment, enter the controlled objects. Existing gas analytical systems do not allow detecting defects at an early stage of their development due to the fact that, with a low concentration of thermal destruction products, they cannot be reliably detected against the background of high concentrations of other gases. Existing gas analytical systems, capable of numerically determining with high accuracy the absolute concentration of a given gas in the air, are used only in narrowly targeted areas due to the complexity of their maintenance, large dimensions and high cost and cannot be used in standard electrical installations.

Thus, there is a need to develop a highly sensitive and reliable gas analytical system for automatically detecting overheating of electrical equipment elements in at least one controlled zone, occurring long before the moment of fire, and taking into account the content of background gases in the air in at least one other controlled zone.

The group of inventions is aimed at increasing the reliability of identifying pre-fire situations occurring as a result of overheating of electrical equipment elements using the gas analytical method.

Terms and definitions used in this group of inventions

The terms presented below are explanatory in nature and do not limit the scope of legal protection of the claimed invention only to the specified wording.

"Running average" is a function whose value at each point of definition is equal to the average value of the original function for the previous period. In relation to the present group of inventions, the running average value of the gas concentration is the average value of the concentrations recorded by the sensor for a certain period up to the present moment.

“External zone” is an area of the electrical installation, fenced off from the controlled area by walls or other partitions and communicating with the environment. In relation to the present invention, the external zone is the area of the electrical installation adjacent to the controlled zone, fenced off from it by a wall or partition, into which the comparison sensor is installed in such a way that the effect on it of the signal gas is minimal.

The term "ignition" refers to the process of a material starting to burn. In relation to the claimed group of inventions, fire includes the beginning of smoldering or burning of cables, contact connections, insulating materials or other elements of electrical equipment as a result of heating by electric current or arc.

“Gas analytical system” is a set of products and devices that make it possible to detect the fact of overheating of controlled elements using the gas analytical method. A gas analytical system may include various gas sensors interconnected by a controller, products or coatings that include thermally activated gas-emitting materials, control and receiving devices that process notifications received from the controller, an alarm system and other elements that provide visualization of the system’s operation, transmission of informing or control messages.

The “gas analytical method for determining overheating of electrical equipment elements” means a method for determining overheating of electrical equipment elements, which consists of registering in the gas phase one or more substances indicating overheating of the controlled element above a certain temperature.

“Gas sensor” is a device designed to determine the content of one or more substances in a gas mixture, generating an electrical signal associated with the concentration of controlled substances in the gas phase and transmitting it to the controller. The following types of gas sensors are distinguished: semiconductor, thermocatalytic, conductometric, electrochemical, optical and other sensors. The sensors used in the present group of inventions are designed to simultaneously detect both background and signal gases.

“Defect” is the non-compliance of an object with the requirements established by the documentation, at least for one indicator.

“Overheat notification” is a set of commands, messages and alerts generated by the controller, intended to inform personnel or related systems about the occurrence of overheating. Notification may include light, graphic, sound, electronic or other types of personnel alerts, a packet of data transmitted to an adjacent system, a change in the position of a dry contact relay, and other actions.

The term “controller” according to the present invention means any logical devices to which at least two gas sensors can be connected via wired or wireless communication; in particular cases, the controller can be connected to one of the sensors by combining it with it. The controller analyzes signals from gas sensors using a set of logical operations and generates a notification informing about the occurrence of overheating. Depending on the user characteristics, the notification can be generated in light, sound, graphic or other form, and can also be a data packet for transmission to adjacent systems or a change in the position of the dry contact relay. The notification may be transmitted by the controller to another device, in particular an external receiving device or a higher-level system. In this case, the notification may additionally include a control command, for example, to break the electrical network, start the fire extinguishing system, and others.

The “controlled area” refers to the area of the electrical installation, fully or partially limited by walls or other partitions, within which there are elements of electrical equipment controlled by one of the system sensors. In a particular case, the controlled area can be the internal volume of an electrical panel, a section of distribution devices, a switch compartment, a box for a distribution unit of windings, etc., within which the elements to be controlled are located. The controlled area may be hermetically or non-hermetically separated from the external area and other controlled areas. The degree of leakage of the controlled area of electrical equipment can be determined by the IP class parameter. In a particular case, the controlled zone may not be separated by partitions from other controlled zones, provided that the signal gas released when the controlled element is heated affects only (primarily) the sensor corresponding to this controlled zone.

The term “controlled element” describes an element of electrical equipment, the overheating of which is determined using a gas analytical system according to the claimed group of inventions.

"Part per million" or "ppm" is a unit of measurement of any relative value, equal to 1⋅10 ^-6 from the base indicator. In relation to the claimed group of inventions, the ppm value means the content of measured gases in the controlled area at a given time and determines the absolute concentration of these gases. Gas concentrations expressed in parts per million can be converted to percentage concentrations as follows: 1% = 10,000 ppm.

The concept of “multiple system activations” characterizes the ability of a gas analytical system to register the fact of overheating in repeated “heating-cooling” cycles more than once without replacing system components.

The term “model gas” means a substance or group of substances that are used when testing a system and include compounds that are similar in one way or another to signal, background gases or substances released when a thermally activated gas-emitting material overheats.

The term “overheating (heating, heating) of electrical equipment elements” refers to the achievement of electrical equipment elements at a temperature exceeding the temperature of normal operation due to the occurrence of a defect, arc discharges and other reasons.

The concept of “threshold concentration of a signal gas” or “threshold of a gas analytical system” is the minimum concentration of a signal gas or the minimum value of the signal from the gas sensor of a gas analytical system at which an alarm is generated.

The term “self-diagnosis” reveals a set of processes performed in automatic mode aimed at determining the operability of the system.

"Comparison sensor" is an additional gas sensor connected to the system of the present invention, designed to be installed near the controlled area and recording the concentration of background gases.

“Gas sensor signal” and “gas sensor signal value” are an electrical signal generated by a gas sensor, one of the parameters of which depends on the concentration of specified substances (for example, signal or background gases) in the gas mixture. In accordance with the present invention, a signal is transmitted from the gas sensor to the controller via wired or wireless communication. The gas sensor may additionally include logic modules that convert or modulate the signal, various filters, signal amplifiers and other components.

The term “signal gas” means a substance or group of substances that are released into the gas phase when the controlled elements or thermally activated gas-emitting materials installed on them are overheated and for which the gas sensor is configured to detect.

The “degree of leakage” of a closed volume characterizes the ratio of the total area of permanently open sections of a given volume to the area of the enclosing structures, expressed as a percentage. The IP rating can also be used to quantify the degree of leakage in electrical cabinets and distribution boards.

The IP code (according to GOST 14254-2015) denotes a codification system used to indicate the degrees of protection provided by enclosing structures from access to hazardous parts, ingress of external solid objects, water, as well as to provide additional information related to such protection.

The term "thermally activated gas-releasing material (TGM)" refers to a material capable of releasing gas when heated above a specified threshold temperature, preferably in the range of 60-150°C. In particular, such material can be part of thermally activated gas-emitting stickers, clips, cambrics, other products, as well as special coatings (varnishes, paints, etc.). The thermally activated gas-releasing material may include microcapsules or microporous components containing signal gases that the gas sensor is configured to detect. The mass fraction of substances that pass into the gas phase when the thermally activated gas-releasing material is heated to a threshold temperature must be at least 30%. The temperature at which a thermally activated outgassing material begins to emit gas is called the offgassing threshold temperature or simply threshold temperature. Depending on the structure of the thermally activated gas-releasing material, when heated to a threshold temperature, complete or partial release of the gas contained in it may occur. In the latter case, when reheated above the threshold temperature, the material will again release part of the gas it contains. This property of TGM provides the possibility of repeated operation of the gas analytical system.

The term “background gas” discloses a substance or group of substances that may be present in the air of the operating area of an electrical installation, can be detected by a gas sensor, and the occurrence of which is not associated with overheating of the controlled elements or thermally activated gas-emitting materials installed on them.

The term “electrical equipment” refers to a set of devices intended for the production, distribution, transmission and consumption of electricity, the basis of which is the principles of electrical engineering.

An “electrical cabinet” or “distribution board” is a frame into which various electrical equipment is installed, including those intended for receiving and distributing energy. An "enclosed electrical cabinet" is an enclosure, usually made of metal or plastic, that is completely or partially enclosed on all sides. The panel differs from the cabinet in that the equipment is mounted in a special niche in the wall and is closed only on the front side.

The essence of the group of inventions

The claimed group of inventions is aimed at increasing the reliability and reliability of identifying the initial stages of defects in electrical equipment elements in a controlled area using a gas analytical method that takes into account the current concentration of background gases in controlled areas. Moreover, the group of inventions uses at least two sensors installed in different controlled zones, and the number of controlled zones, and, accordingly, sensors installed in them, is not limited by an upper limit.

The problem to be solved by the stated group of inventions is to create a gas analytical system for monitoring overheating of electrical equipment elements, a method for testing it, as well as a method for automatically detecting overheating of electrical equipment elements with high reliability and sensitivity.

The technical result of the claimed group of inventions is to increase the reliability and safety of electrical equipment operation due to the timely detection of defects accompanied by overheating of electrical equipment elements.

To achieve the specified technical result, the group of inventions uses the determination of overheating of electrical equipment elements using a gas analytical method using two or more sensors located in different controlled areas of one electrical installation, with at least two sensors designed to detect gases released when the controlled element is heated and/ or thermally activated gas-emitting materials installed on it in two different controlled zones, made with the ability to determine and take into account the concentration of background gases. The controller, connected to the gas sensors, processes the information received from the sensors using special algorithms that make it possible to reliably and reliably detect heating of the controlled elements and minimize the likelihood of false alarms due to the possible presence of background gases. The essence of the algorithm is that the controller analyzes gas concentrations in all controlled areas at once. If a sensor detects gas in one of the controlled zones, which may be associated with either overheating of the controlled element or THM, the controller analyzes signals from sensors in adjacent controlled zones. Since the probability of simultaneous occurrence of defects in two different controlled zones is extremely small, an increase in gas concentration in all zones is taken as the influence of external background gases not associated with overheating, and an increase in concentration in only one zone is taken as the release of a signal gas and an alarm. As has been shown in practice, this approach allows not only to reduce the number of false alarms, but also to significantly reduce the threshold concentration of the signal gas, based on which the system can generate an alarm.

The specified technical result is achieved through the use of a system for automatically detecting overheating of electrical equipment elements, including:

- at least two gas sensors (S1, S2...Sn), designed for installation in at least two different controlled areas to detect gases released when the controlled element is heated or thermally activated gas-emitting materials installed on it;

- a controller configured to connect with at least two gas sensors S1 and S2 and generate a notification about overheating and/or transmit information about such overheating to another device when the sensor S1 detects gases released when the controlled element is heated in one controlled zone or thermally activated gas-emitting materials installed on it, taking into account the concentration of background gases in the air detected by the S2 sensor installed in another controlled area.

An additional group of inventions may include the use of thermally activated gas-emitting materials, predominantly reusable (TGM) and special signal processing algorithms that make it possible to detect a defect before the development of irreversible changes in the structure of the materials of the controlled elements, for example, thermal destruction of insulation. THMs used to detect overheating of electrical equipment elements have a fixed threshold temperature of gas evolution, which, as a rule, is lower than the temperature at which irreversible destruction of electrical equipment elements begins. Thus, the use of THM makes it possible to detect overheating at a stage that allows maintaining the operability of electrical installation elements. In addition, the ability of some THMs to emit a signal gas in repeated heating/cooling cycles makes it possible to repeatedly detect overheating of electrical equipment elements without replacing the system or its individual parts and to clarify the remaining operating life of the equipment.

Elements of electrical equipment are selected as the object of control for the present invention. This is due to several reasons. Firstly, the reliability and reliability of the functioning of electrical installations is an important and integral factor in ensuring the safety and reliability of the operation of almost all types of production, social facilities, transport, urban infrastructure, etc. Secondly, electrical installations are a source of increased fire danger. As already noted at the beginning of the application, fires due to violations of the rules for operating electrical equipment take first place after careless handling of fire. Thirdly, in most cases, electrical installations of a high voltage class do not allow for visual inspection under load, which does not allow timely detection of defects using thermal imaging inspection or other visual inspection methods. Separately, it should be noted that the materials from which electrical equipment is made: wires, cables, insulators or electrical equipment housings are in most cases non-flammable. It is not possible to detect their overheating with standard fire (smoke, heat, infrared and other) sensors.

The need to use at least two gas sensors, each of which can act as a comparison sensor relative to the other, and determine the concentration of background gases in the controlled areas, is associated with the need to generate an alarm about overheating when one of the sensors detects a signal gas in the lowest concentrations. The task of the sensor, acting as a comparison sensor in this case, is to exclude false alarms caused by a constant change in the concentration of background gases in another controlled area. The advisability of monitoring the signal gas in minimum concentrations is associated with the following circumstance. As a rule, the rate of development of defects associated with overheating of electrical equipment depends exponentially on temperature. In other words, the lower the temperature, the slower the defect develops, and the greater the margin of time for repairs or preparation for shutdown. From a technical point of view, it is most advisable to identify defects at the earliest stages of their development. However, with slight overheating, the concentration of released gases is very small. This is due not only to the low rate of the depolymerization reaction, but also to the weathering of the released gases from the electrical installation over time. At the moment, a large number of sensors are known that make it possible to detect products released during the decomposition of insulation, or special signal gases in extremely low concentrations, equal to units or tens of ppm. However, such sensors work well only in an ideal environment, that is, at constant temperature, humidity, CO ₂ content, oxygen and other atmospheric gases. It is impossible to ensure such “ideal” conditions in electrical installations. Changing the impact of the above-mentioned factors during operation leads either to the need to significantly roughen the system and raise the response threshold of the gas analytical system, or to put up with a large number of false alarms. The above circumstance is one of the significant factors limiting the scope of application of the gas analytical system. An equally significant factor is the change in sensor sensitivity over time, as well as the dependence of the sensor signal on temperature, magnetic fields and other factors.

Gas analysis systems must have the necessary versatility and operate efficiently and reliably, regardless of external conditions and the type of insulating materials used. As a rule, it is impossible to predict the environmental conditions under which the system will be operated, as well as the composition and amount of background gases to which the system will be exposed during operation.

Signal gases, which gas sensors used in a gas analytical system are configured to detect, are not an individual substance, but a collection of substances, the qualitative and quantitative composition of which can vary significantly. For this reason, the sensors used in the gas analytical method are, as a rule, tuned not to an individual substance, but to a group of substances united by the presence of one or another structural fragment.

Taking into account that any parameter measured by such sensors directly or indirectly characterizes the concentration (content) of a gas or group of gases in a gas-air environment, in this application the concept of “concentration” will be used when referring to the content of signal or background gases. In this case, the sensor generates a signal, the value of which is determined by the measured parameter of the gas mixture, so we can say that the value of the signal received from the sensor by the controller also characterizes the content of a certain set of substances in the controlled area and is somehow related to their concentration.

The main difficulty in increasing the sensitivity of gas sensors when detecting signal gases is that when the sensor is configured to determine the maximum value of the parameter X - I _max (X), which best characterizes the signal gas (Fig. 6a, solid lines b), it however, it can also detect the presence of other background substances for which the maximum value of the X parameter is close to the detected value. This is due to the fact that, as a rule, graphs of the dependence of the values of these parameters I(X) on the content of given substances have a shape close to the Gaussian distribution. Therefore, even if the maximum values of the X parameters do not coincide, the standard deviation from I _max (X) of background gases (Fig. 6a, dotted lines a) can overlap with I _max (X) of signal gases, which, with a high content of foreign substances, can lead to triggering systems.

The use of products in the system that include thermally activated gas-emitting materials and are installed on the controlled elements, or thermally activated gas-emitting coatings applied to these elements, allows the sensors to be configured to register specific signal gases that are released from these materials upon activation due to heating. Signal gases, as a rule, are selected in such a way that their maximum value of the parameter X - I _max (X) - differs as much as possible from the maximum values of this parameter characteristic of most background gases (for example, CO ₂ , oxygen, water and other atmospheric gases), as shown in Fig. 6a, thick line p. However, in practice, the I(X) dependence recorded by the sensor will look similar to the graph shown in Fig. 6b, and since the content of background gases under certain conditions can be many times higher than the concentration of the signal gas, the area with the maximum value of parameter X, characteristic of signal gases released from the TGM, still overlaps, and false alarms of the system occur.

In this regard, an important task of modern systems for detecting overheating using gas analytical methods is the combination of the ability to register the low content of gases released during overheating of controlled elements of electrical equipment or thermally activated gas-emitting materials installed on them, and minimizing false alarms. We found that taking into account the current content of background gases allows us to greatly increase the sensitivity of the system, as well as significantly reduce the number of false alarms that occur due to the detection of third-party gases by sensors.

The essence of the present invention is that the controller generates an overheating alarm when sensor S1 detects gases released when the controlled elements and/or thermally activated gas-emitting materials installed on them are heated in the first controlled zone (that is, in the zone in which S1 is installed) , taking into account the concentration of background gases determined by sensor S2 located in the second controlled zone (in which S2 is located). At the same time, an alarm notification is also generated if the S2 sensor detects gases released when the controlled elements or thermally activated gas-emitting materials installed on them are heated in the second controlled zone, taking into account the background gases detected by the S1 sensor in the first controlled zone. In the simplest case, an alarm is generated only if the difference between the signals recorded by S1 and S2 exceeds the set threshold value.

The sensors are located in different controlled areas, that is, in such a way that sensor S2 is equally affected by all the same gases that affect sensor S1, with the exception of gases released when the controlled elements are heated and/or thermally activated gas-emitting materials installed on them. In this case, when generating an alarm for each of the sensors, the average signal received from another sensor or the average value from all other sensors is taken as the zero value (baseline). This approach makes it possible to reduce the likelihood of false alarms caused by exposure to background gases on the sensor, and thereby reduce the threshold value of the concentration of signal gases at which an alarm notification is generated. In addition, since sensor S2 is operated under the same conditions as sensor S1, the poisoning of the sensing element, the temperature dependence of the signal, as well as other parameters of sensor S2 and sensor S1 will be equal. This allows us to further increase the sensitivity of the method. Taking into account the exponential dependence of the rate of defect development on temperature, this approach can significantly increase the detection of defects in the early stages and reduce the number of false positives.

In the simplest case, the system takes the value of the signal I ₂ , which characterizes the content of background gases and generated by sensor S2, as the baseline. The controller generates an overheating notification when the value of the signal I ₁ , characterizing the content of signal gases and recorded by sensor S1, deviates from this baseline upward in accordance with the formula: I ₁ - I ₂ >0. If the value of signal I ₁ does not exceed the value of signal I ₂ or the values of these signals are equal, i.e. when I ₁ - I ₂ <=0, the controller does not generate an overheating notification. Thus, the use of the system according to the claimed group of inventions makes it possible to recognize and filter out false positives by comparing the values of the signals recorded by the S1 sensor with the values of the signals recorded by the S2 sensor, using the simplest algorithm given above, or using more complex algorithms disclosed in the description below.

The present invention can use various methods for comparing the values of signals recorded by sensors that characterize the gas content: the absolute values of the signals at each moment in time, the average values of the signals over different time periods, the integral or differential values of the signals can be compared (in the latter case, not the relative values themselves will be taken into account signals, and the rate of their growth), averaged signal values obtained from several sensors acting as comparison sensors or several sensors installed in the controlled area where overheating of electrical equipment elements occurred. All these approaches make it possible to optimize the operation of the system for a specific application task, since each type of defect has its own development characteristics. What is common in all cases is that the signals recorded by sensor S1, which records the total content of background and signal gases, are analyzed taking into account the concentration of background gases detected by sensor S2 and vice versa.

Thus, taking into account the current content of background gases by determining their concentration in the air S2 makes it possible to reduce the threshold concentration of the signal gas required for generating a notification, as well as to recognize and minimize false alarms associated with changes in the composition of background (atmospheric) gases over time. Early detection of defects associated with heating elements of electrical equipment ensures increased reliability and safety of operation of electrical equipment.

The claimed system may contain more than two sensors, and the formation of a notification by the controller takes into account the averaged signals received from various sensors, with the same or different contribution from each individual sensor.

In some cases, the system can implement adaptive operating logic. In this case, the set threshold concentration value changes during operation based on the maximum change (oscillation amplitude) of the signals from sensor S1 or sensor S2 over a long period. This approach is preferable, since depending on the external conditions and features of the controlled electrical equipment, it is not always possible to reliably determine the threshold values of the signal gas, and the use of a single fixed (universal) setting value for all types of electrical installations can lead to either false alarms or, conversely, reducing the sensitivity of the system. In the case of adaptive logic, the controller generates an overheating notification when the signal from sensor S1 exceeds the signal from sensor S2 not by a fixed threshold value, but by a constantly changing threshold value. In the simplest case, the value of the adaptive threshold can be equal to the maximum difference in values between sensor S1 and sensor S2, multiplied by a constant (the value of which is mainly in the range from 2 to 5). In another calculation option, an array of signal values received from all sensors acting as comparison sensors forms the dispersion (i.e., a measure of spread) of the values of background gas signals relative to the average value of these signals. From this data, the controller can also calculate the standard deviation, which is usually the square root of the variance, but is sometimes estimated by other calculation methods. An overheat notification is generated only if the signal recorded by S1 is out of the set formed by the dispersion or standard deviation from the average value of the signals acting as comparison sensors. If the values of S1 lie within the specified set, then an overheating notification is not generated. In this case, the entire set of calculated values is formed depending on the data received from all sensors at each moment in time.

The adaptive threshold value and the use of the system operating principle described above further increases the reliability of detecting overheating of electrical equipment, since it allows one to reduce the absolute value of the threshold concentration, upon determination of which the system is triggered, and makes the system independent of the set threshold values.

The formation of a notification about overheating of electrical equipment elements and/or transmission of information about such overheating to another device can occur when the average value of the signals characterizing the gas content recorded by all or some sensors is exceeded, with the same or different contribution of the signal values recorded by each individual sensor, the specified values . Increasing the number of sensors further improves the reliability of detecting overheating of electrical equipment elements, especially in large-sized electrical equipment, for example, such as large-volume distribution cabinets, since each sensor will analyze a certain volume of air surrounding it. Gases released during overheating of equipment elements or thermally activated gas-emitting materials installed on them are initially localized in the immediate vicinity of the heating site and spread evenly throughout the entire volume of electrical equipment over time due to diffusion processes, the speed of which depends on many factors, for example, forced ventilation . In this case, it is important that the sensor is located as close as possible to the heating site to reduce the delay in the system generating notifications about local overheating. Therefore, placing several sensors in different places of controlled areas will allow timely detection of pre-fire situations associated with the release of polymer insulation products and other materials. In addition, increasing the number of sensors in the system will make it possible to more accurately determine the baseline characterizing the content of background gases by expanding the set of values taken into account during mathematical processing.

In another embodiment, the system may use a combination of fixed threshold and adaptive logic and be based on the calculation and comparison of running averages captured by the sensor. The controller, receiving data from sensor S1, calculates two indicators: a long running average, calculated as the average value of the recorded parameters over a long period of time, characterizing the rate of change in the parameters of the air mixture, not related to the heating of the controlled element (usually 5 minutes - an hour) and a short running average, calculated over a time period equal to the time of active growth in the concentration of signal gases when the controlled element reaches the threshold temperature (preferably 10 seconds 10 minutes). In this case, the long running average actually characterizes the presence of background gases and sets the baseline against which the short running average, which characterizes the average concentration of signal gases, is compared. The threshold value of the difference between the short and long running averages (calculated as the difference of these parameters or using more complex algorithms) can either be set depending on the type of electrical installation, or adjusted automatically taking into account the background gases recorded by the S2 sensor. The accuracy and sensitivity of the system can be adjusted by choosing the time period for calculating the long running average: the longer the period of time taken into account, the less background gases will contribute to the value of the short running average. Such adjustment can also be carried out automatically, depending on the data received from the S2 sensor. The presence of S2 is necessary not only to adjust the adaptive threshold and time period for determining a long running average, but also to confirm that the threshold value has been exceeded by sensor S1, which is necessary in the event of a sharp increase in the concentration of signal gases in the ambient air for reasons not related to heating of the controlled elements.

As a rule, the average volume of the controlled area, for example, one section of electrical equipment (in particular, electrical panels, complete switchgears, low-voltage complete devices, winding distribution box boxes, etc.) ranges from 100 liters to 1000 liters (1 m ³ ). It was experimentally established that the mass of products released from insulating materials during overheating of electrical equipment elements or thermally activated gas-emitting materials installed on them, the content of which is determined by gas sensors, does not exceed 1 g. Under normal conditions, the molar volume of any gas is taken to be 22.4 l/mol , the molar mass of air is 29 g/mol, and the average molar mass of the signal gases is 200 g/mol. Then the concentration of measured products in the controlled area will average 30-300 ppm. Therefore, for reliable and reliable operation, the system must detect the excess of signal gases in the range of 30-300 ppm. At the same time, the concentration of other gases, which can also be captured by sensors, is much higher; for example, the concentration of CO ₂ in the atmosphere can reach 1000 ppm and higher. This fact additionally indicates the need to use a sensor located in another controlled area and detecting the signal from the background gas.

As noted above, in order to continuously monitor the release of gases formed during overheating of electrical equipment elements or thermally activated gas-emitting materials installed on them, it is not advisable to quantify only one specific substance, but it is necessary to record a group of substances similar in structure. For this purpose, it is necessary to select a sensor that changes some parameter upon adsorption of a controlled substance or as a result of a reaction with a certain class of substances. For example, a sensor can measure the conductivity of a medium between two sensitive elements, depending on the composition of this medium, and generate a signal, the value of which will be higher, the higher the content of the gases that caused this change. In this case, the absolute concentration of the signal gases will be unknown, but its change will lead to a change in one of the sensor parameters, which will lead to the formation of a signal by the gas sensor and will indicate a change in the composition of the air environment. Sensors that detect a change in the composition of a gas-air environment by an indirect change in their parameters and generate a signal proportional to this change are widely used in various gas analytical systems due to their convenience, reliability, ease of use, compactness and low cost, and therefore their use is preferable within the stated group inventions.

Semiconductor, thermocatalytic, conductometric, electrochemical, optical and other types of sensors, each of which has a number of features, can be used as gas sensors in the claimed group of inventions.

Thermal catalytic sensors monitor the heat release resulting from the oxidation of the analyzed gas on the surface of a thermocatalytic element, which is a platinum filament heated to a high temperature and coated with a layer of catalyst, and the value of the heat release directly depends on the molar concentration of this gas. Their advantages are high performance and the presence of an explosion-proof shell, however, the thermocatalytic element quickly degrades, and the sensor itself has high energy consumption and requires a constant connection to the electrical network, which limits the scope of their use.

The operating principle of electrochemical sensors is based on the interaction of the analyzed gas with a sensitive layer located directly on the working electrode or in a layer of electrolyte solution near it. Such sensors provide high selectivity and measurement accuracy, however, the presence of a liquid electrolyte reduces their service life and makes them less preferable for use in electrical installations.

Optical gas sensors are based on the absorption of gases at specific wavelengths, typically in the infrared range. In this case, the absorption coefficient is directly proportional to the concentration of gases. The advantage of optical sensors is their long service life and the absence of aging effects, since the sensitive element of the sensor is protected from the effects of the analyzed gases. Sensors of this type can also operate over a wide range of concentrations. However, despite the fact that optical sensors can be tuned to absorb certain wavelengths, such sensors are highly sensitive to the concentration of water, carbon dioxide and other compounds that the atmosphere may contain (for example, flammable liquid vapor). This leads to significant fluctuations in the measured parameters of both the monitoring sensor and the comparison sensor over time. The latter circumstance prevents a decrease in the sensitivity threshold of this type of sensor. Tuning optical sensors to determine the absorption of wavelengths allows increasing selectivity and sensitivity, but significantly complicates the system.

Semiconductor sensors are one of the main types of sensors used in gas analytical systems. Their principle of operation is based on a change in the resistance of the sensitive layer when exposed to the measured gas. As such a sensitive layer, as a rule, wide-gap semiconductors are used (oxides and chalcogenides of metals: SnO ₂ , ZnO, TiO ₂ , WO ₃ , SnO ₂ , etc.), reversible chemisorption of the measured gases on which leads to reversible changes in conductivity. Their advantage is not only high sensitivity, a wide dynamic range of measured concentrations, but also low energy consumption.

The preference for using sensors of this type for the claimed system for automatically detecting overheating of elements of electrical equipment is due to the fact that when the insulating materials of the controlled elements of electrical equipment overheat, usually including cross-linked polyethylene (PE), polyvinyl chloride (PVC), rubber, silicone, epoxy resin, etc. ., reducing gases are released (for example, ethylene, vinyl chloride, isoprene, butylene, HCl, H ₂ , CO, etc.), which can be determined by oxidizing semiconductor materials in low concentrations. At the same time, semiconductor sensors react poorly to the products of complete oxidation of organic substances, for example, CO ₂ , oxygen, and other substances with low reactivity, which are present in the air in relatively high concentrations. This makes it possible to further increase the sensitivity of the system and ensure its reliable operation at low concentrations of substances formed as a result of overheating of electrical equipment elements (for example, the occurrence of partial arc discharges), indicating the initial stage of development of a defect.

At the same time, it should be noted that the claimed group of inventions is not limited to the use of a certain type of gas sensor. For reliable and reliable operation of the claimed group of inventions, an important criterion when choosing the type of sensors used is the selective registration of products released during overheating of the insulating materials of electrical equipment elements or thermally activated gas-emitting materials installed on them, relative to gases that may be present in the atmosphere during normal operation of the system. These gases include: flammable liquids used in the maintenance of electrical installations, as well as during repair and paint work; flue gases released during the operation of internal combustion engines, boilers, gas turbines, etc.; methane, gasoline or diesel fuel vapors, emissions from chemical plants, etc.

All the sensors described above, which can be used in the stated group of inventions, provide continuous and repeated registration of products released during overheating of controlled elements of electrical equipment or thermally activated gas-emitting materials installed on them, as well as background gases both in the controlled area and outside it. throughout the entire service life, which also ensures reliable detection of overheating of electrical equipment elements.

In the preferred embodiment, the sensors used in the claimed system are semiconductor type sensors, the sensitive element of which is designed to continuously or repeatedly detect gases released when heating insulating materials, including, in particular, cross-linked polyethylene (PE), polyvinyl chloride (PVC), rubber, silicone, epoxy resin. In particular, the sensors are designed to record these gases in concentrations from 30-100 ppm.

To increase the sensitivity of the system and detect defects with a heating temperature below the thermal destruction temperature of insulating materials, in addition to a comparison sensor, it is preferable to use thermally activated gas-emitting materials (TGMs). In particular cases, the sensitive element of the sensors is designed to register products released during overheating of thermally activated materials, preferably of multiple action, included in products or coatings installed or applied to controlled elements of electrical equipment.

THMs contain an encapsulated or otherwise hermetically sealed signal gas from the environment, the release of which occurs at a relatively low temperature. Encapsulated materials existing on the market have a high content of signal gases (more than 30%) and an initial gas release temperature that is set with sufficiently high accuracy. THMs are usually used in special stickers, clips, varnishes or coatings.

Thermally activated gas-emitting materials are suitable for use in the following cases:

- control of heating of metal elements that are not coated with polymer materials and are not capable of releasing a signal gas when overheated;

- control of other elements of the electrical installation at a temperature below the beginning of decomposition (thermal destruction) of polymer materials;

- selective control of individual elements (those on which TGMs are applied or installed);

- increasing the sensitivity of the system and reducing the number of false alarms due to the fact that the amount of signal gases released from the THM is significantly higher than during the decomposition of polymer insulation. The signal gases contained in the THM can be selected in such a way that the sensitivity and selectivity of the sensor with respect to these gases is maximized.

Another advantage of using thermally activated gas-emitting materials is the possibility of recording the heating temperature of the controlled element through the use of THM with a given threshold temperature.

The release of gas from thermally activated materials when heated to a threshold temperature, as a rule, occurs abruptly, which leads to a sharp increase in the concentration of signal gases. This makes it possible to increase the reliability of detecting overheating of electrical equipment elements, especially in relation to the system operation algorithms described in this application. In addition, as mentioned above, the signal gases used in TGM are usually selected in such a way that their measured parameters are outside the areas overlapped by the parameters of the background gases, which allows for more selective tuning of the sensitive elements of the sensors, thereby increasing their sensitivity . High sensitivity allows the use of products containing THMs of relatively small sizes, for example, stickers 1-20 cm long and 0.5-5 mm thick, or coatings containing THMs. On the one hand, the content of signal gases in such products (coatings) is low, due to the small volume of the heat-sensitive layer. On the other hand, this amount is sufficient for reliable detection of overheating. The small size of products containing THMs allows them to be installed on small elements of electrical installations: wires with a cross-section of 0.75 mm ² , terminal blocks, blocks, circuit breakers and other small equipment, the control of overheating of which is impossible by other methods. Another important advantage of increasing sensitivity by the described method is the possibility of using the invention, including THM, even in ventilated electrical installations.

Thus, the use of the system according to this group of inventions in conjunction with TGM can significantly increase sensitivity, reduce the likelihood of false alarms and register the achievement of heating of local elements to specified temperatures before the development of emergency defects or fire.

In electrical equipment, as a rule, heating is associated with the current value of the load current. Most often, the dependence is quadratic and obeys the Joule-Lenz law. The load on electrical equipment often changes significantly during operation, so after a fault occurs, overheating can recur many times. In this case, the insulation materials of the heated element will gradually, from cycle to cycle, release a small portion of the signal gas, until the complete destruction of the material. In this case, the system according to the claimed group of inventions will generate a notification each time it is heated, which can further increase the likelihood of timely detection of a defect and increase operational reliability. In the case of thermally activated gas-emitting materials, as mentioned above, multiple registrations can be ensured by the structural features of the THM, for example, the content of a large number of microencapsulated particles of different sizes and with different opening temperatures.

In the claimed group of inventions, as products including THMs, it is preferable to use thermally activated reusable gas-emitting stickers made of a polymer composite material containing a continuous phase formed by a thermosetting polymer, the pores of which are filled with a sulfur-containing odorant or freon [EA 201890482, publication date 06/29/2018] . Thanks to the special structure of the material and the use of thermosetting polymers, when a given temperature is reached, only part of the pores are opened, releasing the gas contained in them and maintaining the integrity of the remaining pores, which ensures repeated gas release in repeated heating/cooling cycles. Therefore, the use of such thermally activated stickers makes it possible to repeatedly detect overheating of electrical equipment elements without replacing the system or its individual parts. In addition, in these stickers, the combination of a polymer composite material with odorants filling its pores ensures not only the integrity of the material at temperatures close to, but not yet reached the opening temperature, but also the explosive destruction of part of the pores when heated to threshold values, leading to the immediate release of sufficient for detecting the amount of signal gas by the sensor. Thus, the use of predominantly thermally activated gas-emitting stickers, described in the source [EA 201890482], ensures multiple operation of the system according to the stated group of inventions, as well as its speed.

In a preferred embodiment, S1 and S2 have a sensing element of the same type and are configured to register gases belonging to classes of compounds selected from the list: halocarbons, hydrogen halides, halohydrocarbons, alkenes, alkanes, mercaptans, acids or mixtures thereof, preferably gases selected from the list: carbon tetrafluoride, tetrafluoroethylene, tetrachlorethylene, trifluoromethane, chloroform, dichloromethane, methyl chloride, methyl bromide, trifluoromethane, ethyl chloride, vinyl chloride, hydrogen fluoride, hydrogen chloride, ethylene, propylene, butadiene, isoprene, methane, ethane, butane, hexane, methyl mercaptan, id, ethyl mercaptan, diethyl sulfide, nitric acid, nitrous acid or mixtures thereof.

As noted above, the sensors of the gas analytical system according to the stated group of inventions form a response (signal) not to any specific gas, but, most often, to several gases (gas mixture) to which the system sensors are configured. At the same time, some gases can make a greater contribution to this response, while others less. Thus, each sensor must be installed in such a way as to detect to the maximum extent the products released when the controlled elements or thermally activated gas-emitting materials installed on them are overheated in a separate controlled zone, and to a minimum extent to detect the products released when the controlled elements are overheated or installed on them. of thermally activated gas-emitting materials in any other controlled area. It is preferable to install each sensor above the controlled element in separate sections of electrical equipment (for example, electrical panels, complete switchgears, low-voltage complete devices, distribution box boxes of the windings, etc.). It is also possible to arrange at least two sensors S1 and S2 in one section of electrical equipment in such a way that each of the sensors determines the gas environment only of its controlled zone, while not experiencing or experiencing minimal influence of gases released in other controlled zones. In this case, the gas released from the controlled element is captured by only one of the sensors. In particular, one sensor can be installed in the upper and the other in the lower parts of one section of electrical equipment, while there may be no partitions or walls limiting them between the monitored areas.

The values of the signals characterizing the content of gases, for the detection of which the sensitive elements in sensors S1 and S2 are configured, are transmitted to the controller, which processes the data received from both sensors either simultaneously or with a certain time delay, determined experimentally for a specific electrical installation.

The controller according to the claimed group of inventions is configured to generate an overheating notification after receiving and processing, using a set of logical operations, data received from the sensors associated with it. The controller can provide notification of overheating of the controlled elements in the form of a sound, light, graphic or other notification, or in the form of a control command, for example, to turn off or reduce the load. The controller can also transmit the generated notification to another device, for example, to an external receiving device. The type of notification used about the occurrence of a pre-fire or emergency situation is determined on the basis of the technical documentation of the controlled electrical equipment, as well as the ease of use of the system. The controller can be combined with one of the gas sensors and connected to the remaining sensors of the system via wired or wireless communication, or it can be made as a separate device that communicates with all sensors of the system via wired or wireless communication.

In particular cases, the controller is configured to generate an overheat notification when sensor S1 detects gases released when the controlled elements overheat in a concentration above a specified limit value, regardless of the current concentration of background gases detected by sensor S2. This feature allows you to identify rapidly developing defects that lead to instant heating, fire and excess concentration of signal gases in all controlled areas of the electrical installation. In this case, timely shutdown of the electrical installation helps prevent the development of a fire and minimize damage to adjacent equipment.

To further ensure the reliability and reliability of detecting overheating of electrical equipment elements, the claimed system can use various algorithms when generating a notification about overheating of electrical equipment elements and/or transmitting information about such overheating to another device.

The controller may use one or more of the following algorithms to process signals received from gas sensors:

- calculation of the running average value from each sensor for a given period of time;

- adjustment of the reference (zero) value;

- defining the reduced running average value as the difference between two running average values received from one sensor over two different periods of time, preferably a short period of less than one minute and a long period of more than 5 minutes;

- comparison of the given running average value with a threshold value and generation of an overheating notification if it is exceeded;

- determination of the average signal value received from different sensors by averaging the given running average values;

- comparison of the difference between the reduced running average values of signals from the comparison sensor and the monitoring sensor, including those calculated for different time periods, with a specified threshold value;

- determination of the growth rate of the reduced running average value and its comparison with the established threshold value;

- comparison of the signal received from the monitoring sensor with the set threshold value;

- determining the growth rate of the difference between the reduced running average value of the signal from the monitoring sensor and the comparison sensor and comparing it with the set threshold value;

- determination or change of threshold values based on the analysis of signal values received from sensors during operation;

- adaptive response threshold.

The implementation of the claimed group of inventions using the specified algorithms will be described in more detail in the section “Implementation of the invention”.

In particular cases, the system according to the claimed group of inventions can additionally be equipped with temperature sensors to further increase the accuracy and determine the numerical value of the temperature to which heating has occurred.

In preferred embodiments, the claimed system additionally has a self-diagnosis function, which makes it possible to inform personnel about the need to replace the sensitive element of the sensors, which increases the reliability of the system and electrical equipment as a whole. Diagnostics of sensors, as a rule, consists of regularly automatically measuring the resistance of the sensing element and/or heater or other sensor parameters and generating an appropriate notification when the resistance value goes beyond the established limits or communication is lost.

In a particular case, the controller is configured to generate a notification about overheating of the controlled element and/or transmit information about such overheating to another device when at least one sensor detects gases released when the controlled element overheats in a concentration exceeding a threshold value that takes into account the content of background or other gases that affected the sensors during the previous period of time.

In the second option, the specified technical result is achieved through a method of testing the specified system, including the following actions:

- installation of S1 in the first gas chamber and installation of S2 in the second gas chamber, connecting the controller to the specified sensors;

- registration of the fact of operation of the system in the absence of influence of model gases on S2 by heating the model element in the first chamber and/or determining threshold concentrations by dosing model gas at a given concentration into the first chamber;

- registration of the fact that the system does not operate when dosing model gas into both chambers

and/or

determination of threshold concentrations by separate dosing of model gas into both chambers.

In this case, heating the model element may include heating a thermally activated gas-emitting material, preferably included in a thermally activated gas-emitting sticker, preferably of multiple action, installed on the controlled element in a gas chamber with a controlling sensor.

The controller can also be combined with one of the sensors. In this case, such a sensor combined with the controller is installed in one of the gas chambers, and another sensor installed in another gas chamber is connected to the controller via wired or wireless communication.

This method provides a clear, regulated check of the system’s compliance with the conditions and algorithms described in the first object of the claimed group of inventions for its further use in identifying overheating of electrical equipment elements.

In the third embodiment, the specified technical result is achieved through a method for automatically detecting overheating of electrical equipment elements, including:

- placement of the system according to claim 1, in which at least one gas sensor S1 is installed in one controlled area and gas sensor S2 is installed in another controlled area;

the controller is installed in an arbitrary location and communicates with at least two gas sensors, including at least S1 and S2, by wired or wireless communication;

- processing of an overheating notification generated by the controller with subsequent issuance of an information message and/or transfer of data to another device connected to the controller.

Each sensor ( _Sn ) can be installed inside an electrical installation near the controlled elements of electrical equipment, that is, inside a separate controlled zone, in such a way as to register products released when the controlled elements of electrical equipment or thermally activated gas-emitting materials installed on them overheat. In this case, each sensor S will detect signal gases released when the controlled elements of electrical equipment or thermally activated gas-emitting materials installed on them are overheated only in the controlled area in which it is installed, without the possibility or with minimal possibility of determining the signal gases released when the controlled elements of electrical equipment overheat or thermally activated gas-emitting materials installed on them in any other controlled areas. However, all installed sensors will be equally exposed to background gases.

Sensors can be installed inside one section of an electrical installation, but in different parts of it in such a way that each sensor detects the gas environment in its controlled area and does not experience or experience minimal impact from signal gases released in another controlled area. In this case, the controlled zones may not be separated by partitions or walls, and the gases released from the controlled element are preferably captured by one of the sensors. In a particular case, both sensors S1 and S2 can be installed inside one electrical panel, switchgear, low-voltage complete device, BRNO box, as well as inside one section of other types of closed electrical equipment, so that one of the sensors S1 is installed at the top, and the other - S2 - at the bottom of this electrical equipment.

In one of the embodiments of the claimed group of inventions, the system may also include a comparison sensor S _cp , which can be installed in the external zone, i.e. outside all controlled zones, but not far from them, in such a way as to determine the concentration of background gases without monitoring the products released when the controlled elements or thermally activated gas-emitting materials installed on them are overheated in all controlled zones. The comparison sensor can also be located in another part of the electrical installation. It is permissible to install the reference sensor in at least one controlled area, but with ventilation and in a location where the exposure of the signal gas to the reference sensor will be minimal. For example, in the place of air flow or in the lowest part of the installation. The possibility of such installation of a comparison sensor is due to the fact that the products released when the controlled elements of electrical equipment or thermally activated gas-emitting materials installed on them overheat, have a temperature higher than the ambient temperature and rise to the upper part of the controlled zone.

In a particular case, the controller can also generate an overheat notification when at least one of the sensors detects gases released when the controlled elements overheat in a concentration above a specified limit value, regardless of the content of background gases detected by at least one other sensor.

In particular cases, the method can be intended to detect overheating using thermally activated gas-emitting materials, mainly of repeated action, included in products or coatings installed or applied to controlled elements.

If the controller is combined with one of the gas sensors, it is placed in accordance with the location of this gas sensor, while the remaining sensors of the system communicate with it via wired or wireless communication. In the case of a separately implemented controller that communicates with all sensors of the system via wired or wireless communication, its placement does not affect the operation of the system according to the invention. It is noted that it is recommended to install the controller in a place convenient for installation and maintenance during system operation.

The group of inventions, in particular cases, is intended to detect overheating of contacts and contact connections of closed electrical equipment, including contact connections of electrical panels, complete switchgears, low-voltage complete devices, distribution unit boxes and windings. Also, a group of inventions may be intended to detect overheating of insulating materials of electrical equipment elements, including cable couplings, as well as to prevent fires and identify defects in the insulating materials of electrical equipment elements resulting from the passage of arc discharges.

Brief description of drawings

The group of inventions will be more clear from the description, which is not restrictive and is given with reference to the attached drawings, which show:

Fig. 1 A system for automatically detecting overheating of electrical equipment elements, including two gas sensors S1 and S2, each of which is installed inside a separate controlled area near the controlled elements of electrical equipment, and a controller connected to both sensors by wired (a) or wireless (b) communication.

Fig. 2 A system for automatically detecting overheating of electrical equipment elements, including two gas sensors S1 and S2, each of which is installed inside a separate controlled area near the controlled elements of electrical equipment, and a controller connected to both sensors by wired (a) or wireless (b) communication, with the controlled element additionally contains a thermally activated gas-releasing material (TGM). In fig. Figure 2 shows a special case using a thermally activated gas-emitting sticker as a THM.

Fig. 3 - System for automatic detection of overheating of electrical equipment elements, including two gas sensors S1 and S2, each of which is placed in a separate gas chamber (a) or in a separate gas chamber containing a heating element with or without THM (b), and a controller connected with both sensors wired. In fig. Figure 3b shows a special case using a thermally activated gas-emitting sticker as a THM.

Fig. 4 System for automatic detection of overheating of electrical equipment elements, including several gas sensors Sm, each of which is installed inside a separate controlled zone near the controlled elements of electrical equipment, a comparison gas sensor S _cp installed in the external zone, outside these controlled zones, and a controller connected to all sensors wired (a) and wireless (b) communications. In fig. Figure 4 shows a special case with three monitoring sensors (m=3).

Fig. 5 - System for automatic detection of overheating of electrical equipment elements, including two gas sensors S1 and S2, one of which (S1) is installed in the upper part of the electrical equipment section near the controlled element of electrical equipment, and the other (S2) is installed in the lower part of the same electrical equipment section, remote from controlled element, and a controller connected to both sensors by wired (a) and wireless (b) communication.

Fig. 6 - Schematic graph of the dependence of the intensity I of the signal recorded by the gas sensor on the parameter X of the gas mixture separately for background gases, products released during overheating of the controlled elements of electrical equipment, and gases released during heating of thermally activated gas-emitting materials installed on the controlled elements of electrical equipment (a) and in generalized form (b).

In fig. Figure 1 shows a system for automatically detecting overheating of elements of electrical equipment, placed on electrical equipment in such a way that each gas sensor S1 and S2 5 is located in a separate controlled zone 1, in close proximity to the controlled elements of electrical equipment 2, to enable registration of products 4 released during heating 3 of this element, while both sensors are connected to the controller 7 by wired (Fig. 1a) or wireless (Fig. 1b) connection 10 or 11, respectively (system options).

In fig. Figure 2 shows a system for automatically detecting overheating of electrical equipment elements, placed on the electrical equipment in such a way that each gas sensor S1 and S2 5 is located in a separate controlled zone 1, in close proximity to the controlled elements of electrical equipment 2, on which the TGM 8 is located, to enable product registration (gases) 4 released when this material 8 is activated as a result of heating 3 of this element, while both sensors are connected to the controller 7 by wired (Fig. 2a) or wireless (Fig. 2b) communication 10 or 11, respectively (system options) . In fig. Figure 2 shows a special case in which a thermally activated gas-emitting sticker is used as a THM.

In fig. Figure 3 shows a system for automatically detecting overheating of electrical equipment elements installed in gas chambers to illustrate the method of use and method of testing this system, in such a way that each gas sensor S1 and S2 5 is placed in a separate gas chamber 9 (Fig. 3a). In fig. 3b, one gas sensor S1 5 is placed in one gas chamber 9 containing a controlled heating element 2, and another gas sensor S2 5 is placed in another gas chamber 9 containing a controlled heating element 2, on which the TGM 8 is located (in Fig. 3b as An example of the use of TGM is a thermally activated gas-emitting sticker), while the heating element 2 and TGM 8 emit gases 4 as a result of heating 3, the sensors are configured to register them, and both sensors are connected to the controller 7 by wire connection 10 (system options).

In fig. Figure 4 shows a system for automatically detecting overheating of electrical equipment elements, located on electrical equipment consisting of three closed controlled zones 1 EO1-EO3, such that each gas sensor S1-S3 5 is located in a separate controlled zone 1, in close proximity to the controlled elements 2 inside corresponding controlled zones 1 EO1-EO3 to ensure the possibility of recording products 4 released when heating 3 of these elements, the reference gas sensor S _cp 6 is located in the external zone outside the controlled zones 1, outside the closed volumes of electrical equipment so as to register background gases without taking into account the content products 4 released when 3 controlled elements 2 are heated, while all sensors are connected to the controller 7 by wired (Fig. 4a) or wireless (Fig. 4b) communication 10 or 11, respectively (versions of the system with one comparison sensor and three control sensors ).

In fig. Figure 5 shows a system for automatically detecting overheating of electrical equipment elements, placed on the electrical equipment in such a way that the gas sensor S1 5 is located in the upper part of the electrical equipment section in the controlled zone 1, in close proximity to the controlled element 2, to enable registration of products 4 released during overheating 3 of this element, and the gas sensor S2 5 is located in the lower part of the same section of electrical equipment in another controlled zone 1 so as to register background gases without registering products 4 released during overheating 3 of the controlled element 2, while both sensors are connected to a 7-wire controller ( Fig. 5a) or wireless (Fig. 5b) communication 10 or 11, respectively (system options).

In fig. 6a schematically shows an approximate graph of the dependence of the intensity (I) of the signal recorded by the gas sensor on the parameter of the gas mixture (X) separately for background gases (dashed line, a), products released during heating of the controlled elements of electrical equipment (solid line, b ), and signal gases (thick line, c). The graph shows the possible overlap of the signal characterizing the content of products released during heating of the controlled elements with signals characterizing the content of background gases, even in the region of maximum intensity _Imax , as well as the preferred location of the signal characterizing the content of gases released from thermally activated gas-emitting materials relative to the signals characterizing the content of background gases. In fig. Figure 6b schematically shows an approximate graph of the dependence of the intensity (I) of the signal recorded by the gas sensor on the parameter of the gas mixture (X) in a generalized form.

Implementation of the claimed group of inventions

The group of inventions may be intended to detect overheating of conductive elements, cables and cable couplings, contacts and contact connections, as well as other elements of closed electrical equipment, including contact connections of electrical panels, complete switchgears, low-voltage complete devices, distribution unit boxes and windings. Also, a group of inventions may be intended to detect overheating of insulating materials of electrical equipment elements, including cable couplings, to prevent electrical equipment fires, and to identify defects in the insulating materials of electrical equipment elements resulting from the passage of arc discharges.

In accordance with the first variant of the claimed group of inventions, the system for automatically detecting overheating of electrical equipment elements (Fig. 1-2) includes: at least two gas sensors 5 (S1, S2), intended for installation in at least two different controlled zones 1 for detection of gases 4 released when heating 3 controlled elements 2 or thermally activated gas-emitting materials 8 installed on it; a controller 7 configured to connect with at least two gas sensors 5 S1 and S2 and generate a notification about overheating and/or transmit information about such overheating to another device when the sensor 5 S1 detects gases 4 released during heating 3 of the controlled element 2 in one controlled zone 1 or thermally activated gas-emitting materials 8 installed on it, taking into account the concentration of background gases in the air of another controlled zone 1, detected by sensor 5 S2 installed in another controlled zone.

Sensors with various types of sensitive elements and based on the detection of various air parameters can be used as gas sensors in the claimed group of inventions. In particular, such sensors can be semiconductor, thermocatalytic, conductometric, electrochemical, optical and others.

If there are more than two sensors 5 in the system, their operating principles may differ. However, in preferred embodiments, the condition for the controller 7 to generate an overheating notification is to register the impact on one sensor of products 4 released during heating 3 of the controlled element 2 or thermally activated gas-emitting materials 8 installed on it, taking into account the concentration of background gases detected by other sensors having sensor of the same type as the first sensor.

The type of sensors, their sensitivity and quantity are determined based on the specific task to be solved by the use of the claimed group of inventions, the type of electrical equipment being controlled and other factors. It is most preferable to use semiconductor-type sensors in the system according to the claimed group of inventions, the sensitive element of which is designed to detect gases released when heating the following types of insulating materials, including, in particular, cross-linked polyethylene (PE), polyvinyl chloride (PVC), rubber, silicone, epoxy resin, as well as when heating thermally activated gas-emitting stickers installed on the controlled elements, due to the higher sensitivity of such sensors to the products of thermal destruction of the insulating materials of the controlled elements of electrical equipment, lower energy consumption and longer service life compared to other sensors

The system may additionally include thermally activated gas-emitting materials, mainly reusable, included in the composition of products or coatings installed or applied to the controlled elements.

Gas sensors 5-6 according to the stated group of inventions should preferably have the following technical characteristics: the minimum threshold concentration of controlled gases is 100 ppm for freons and CO, 50 ppm for alkanes (C _n H _2n+2 ) and alkenes (C _n H _2n ) with n<4; structurally executed in the form of a single module; The supply voltage of the sensors is 5 V DC; service life is at least 10 years from the date of manufacture.

To detect overheating of electrical equipment elements that are not covered with insulating or other materials that are subject to thermal destruction or other types of decomposition when the temperature rises, the system may contain special thermally activated gas-emitting materials (TGM), preferably reusable, which emit signal gases when heated above a threshold temperature (Fig. 2). Such materials can be part of thermally activated gas-emitting stickers 8, clips or cambrics, as well as thermally activated paints, varnishes or coatings, and can be installed or applied to controlled non-insulated elements of electrical equipment 2, when heated 3 of which the integrity of the THM layer 8 is damaged and the content contained in the material is released. gas 4, which the gas sensor 5 is configured to detect. The advantage of using such materials is that, as a rule, they contain gases that are rarely found in the air under normal conditions, even near such sources of third-party gases as large chemical plants, busy highways and etc. In addition, THMs have the ability to repeatedly release gas in repeated heating/cooling cycles, which makes it possible to repeatedly detect overheating of electrical equipment elements without replacing the system or its individual parts.

The claimed group of inventions primarily uses thermally activated reusable gas-emitting stickers produced by ThermoElectrika LLC and made of a polymer composite material containing a continuous phase formed by a thermosetting polymer, the pores of which are filled with a sulfur-containing odorant or freon. In this case, the system's sensors are tuned to selective gases released from these thermally activated gas-emitting stickers. The advantage of these stickers is that with a single heating to a temperature exceeding the threshold, only part of the pores filled with odorant are opened and gas is partially released. The ability of these stickers to repeatedly release signal gases in repeated cycles of heating to a threshold temperature and cooling ensures repeated activation of the system according to the claimed group of inventions.

Mainly, TGM 8 must have the following set of technical characteristics: signal gas content - at least 50%; the response temperature is in the range of 80-150°C; the signal gas released from the THM has a hazard class of at least 4 and an electrical strength of at least 15 kV/cm; the threshold sensitivity of sensors to the signal gas released from THM is at least 100 ppm; do not emit harmful substances and are classified as low-hazard in terms of the degree of impact on the human body; retain their characteristics after five times exposure from the minimum operating temperature to a temperature 10°C below the response temperature. In particular, thermally activated gas-emitting stickers, in addition to the above characteristics, must also have adhesion of the adhesive layer to stainless steel of at least 15 N/25 mm and stability of the adhesive layer under conditions of exposure to various oils, fats, water, acids, salts, alkalis, and solvents; have an electrical strength of at least 18 kV/mm; minimum bending radius at 24°C - 2 mm, at 0°C - 12 mm; service life is at least 10 years from the date of manufacture.

In a preferred embodiment, the sensors 5 are configured to determine gases belonging to classes of compounds selected from the list: halocarbons, hydrogen halides, halohydrocarbons, alkenes, alkanes, mercaptans, acids or mixtures thereof, preferably gases selected from the list: carbon tetrafluoride, tetrafluoroethylene, tetrachlorethylene, trifluorochloromethane, chloroform, dichloromethane, methyl chloride, methyl bromide, trifluoromethane, ethyl chloride, vinyl chloride, hydrogen fluoride, hydrogen chloride, ethylene, propylene, butadiene, isoprene, methane, ethane, butane, hexane, methyl mercaptan, dimethyl sulfide, ethyl mercaptan, diethyl sulfide, nitric acid, nitrogen exhausted acid or mixtures thereof.

For reliable and reliable operation of the system, the presence of two sensors is necessary and sufficient (Fig. 1). In this case, each sensor 5 can be installed inside a separate controlled zone 1 near the controlled elements of electrical equipment 2 in such a way as to determine the concentration of products 4 released when heating 3 controlled elements of electrical equipment 2, with minimal or no exposure to gases released during heating of the controlled elements of electrical equipment installed in another controlled area, and also to take into account the concentration of background gases in the air. In this case, when the controlled elements or thermally activated gas-emitting materials installed on them are heated in the controlled area in which S2 is installed, the detection of these gases will take into account the concentration of background gases determined by the S1 sensor, that is, their roles in the system will change.

It is also possible to arrange at least two sensors S1 and S2 in one section of electrical equipment in such a way that each of the sensors determines the gas environment only of its controlled zone, while not experiencing or experiencing minimal influence of gases released in other controlled zones. In this case, the gas released from the controlled element is captured by only one of the sensors. In particular, one sensor can be installed in the upper and the other in the lower parts of one section of electrical equipment, while there may be no partitions or walls limiting them between the monitored areas.

In the simplest case, when using a system with two sensors, the analysis of signals received by the controller from these sensors is carried out by comparing their difference, calculated as the difference in signal values or using more complex algorithms, including with a predetermined threshold value.

However, the claimed system may contain more than two sensors 5. In this case, the formation of a notification about overheating of the controlled element and/or transmission of information about such overheating to another device can occur taking into account the average value of gas concentrations determined by all or some sensors 5, with the same or different contribution of the content of background gases, the concentration of which is determined by each individual sensor 5. The system can also generate a notification about overheating 3 of the controlled element 2 and/or transmit information about such overheating to another device when the average concentration of gases detected by all or some sensors 5 is exceeded identical or different contribution of the exceeded concentration of products 4 released during heating of 3 controlled elements 2 of electrical equipment or thermally activated gas-emitting materials 8 installed on them, detected by each individual sensor 5, specified threshold values.

In particular embodiments, the system may additionally contain a comparison sensor S _cp 6 (Fig. 4), installed outside the controlled areas, but in their vicinity, so as to determine the concentration of background gases without monitoring the products 4 released when heating 3 controlled elements 2 In the simplest case, when using a system with one S _cp 6, the analysis of signals received by the controller from sensors 5 and comparison sensor 6 is carried out by comparing their difference, calculated as the difference in signal values or using more complex algorithms, including those with a predetermined algorithm. threshold value. If the system contains more than one S _cp 6, the formation of a notification about overheating of the controlled element and/or transmission of information about such overheating to another device can occur taking into account the average value of gas concentrations determined by all or some S _cp 6, with the same or different the contribution of the content of background gases, the concentration of which is determined by each individual S _cp 6.

The system according to the present group of inventions can operate without a specified threshold concentration value. In this case, controller 7 can also take into account the values of gas concentrations received from all or some sensors S, but the comparison of data received from each sensor will not occur with a fixed threshold value, but, for example, with a dynamic average value that is calculated at each moment in time and in a certain way depends on the concentrations recorded by all or some sensors.

In another embodiment of the claimed system, the baseline characterizing the background content of gases is determined by the value of the long running average values of the signals received from each sensor 5, and the current content of signal gases 4 in the controlled zone 1 is determined as the short running average value of the signals of this sensor 5. Advantageously , the time period for calculating the long running average is more than 5 minutes, and the time period for calculating the short running average is less than 1 minute. Taking into account signals received from other sensors 5, in this case, allows not only to cut off false alarms caused by changes in the concentration of background gases, but also to adjust the optimal time period of running average values and adjust adaptive thresholds.

Other possible algorithms for the operation of the system according to the claimed group of inventions are discussed in more detail below.

Regardless of the implemented algorithm for generating an overheat notification, the controller 7 is preferably designed to take into account the concentration of background or signal gases that affected the sensors 5 during the previous period of time.

Preferably, the sensors are configured to take into account the current content of background gases recorded in the range of 10-10000 ppm.

In particular cases, the system according to the claimed group of inventions can additionally be equipped with temperature sensors to further increase the accuracy and determine the numerical value of the temperature to which heating has occurred. The presence of a temperature sensor allows you to further ensure the safety of using not only the controlled electrical equipment, but also the system itself as a whole. In addition, the value of the recorded temperature can influence the threshold settings when using a particular algorithm or in the case of adaptive thresholds.

All sensors 5 present in the system are connected to the controller 7 using a wired 10 or wireless 11 connection. The controller can also be connected to one of the gas sensors by alignment and communicated with the rest of the system sensors via wired or wireless communication. Thus, the controller 7 is configured to generate a notification about overheating when receiving and processing data from all sensors present in the system using a set of logical operations.

Depending on the task at hand, the controller 7 can issue both a notification informing about overheating of the controlled elements 2 of electrical equipment, in the form of a sound, light, graphic or other notification, and a control notification, for example, to turn off the power supply to emergency equipment. Also, the controller 7 can transmit a notification about overheating of the controlled elements of electrical equipment to an external receiving device or provide a combined notification, for example, transmitting a notification about overheating of the controlled elements of electrical equipment to an external receiving device and a control notification to the control elements of the controlled electrical equipment. The type of notification used regarding overheating of controlled elements is determined on the basis of the technical documentation of the controlled electrical equipment, as well as the ease of use of the system.

The controller 7 used for the claimed system may preferably have the following technical characteristics: the presence of an RS-485 digital communication line interface; Availability of Modbus RTU digital communication line protocol; has the following control and indication elements: buttons for setting parameters, digital indicator for displaying the device address and setting parameters, LEDs for the status of connected sensors; supply voltage ranges from 12 to 28 V DC (nominal value 24 V); has EMC compatibility in accordance with GOST for residential, commercial and industrial areas with low energy consumption or for substations and power plants; the degree of protection of the housing is at least IP 20; presence of a discrete output "Alarm"; service life is at least 10 years from the date of manufacture.

The controller 7 can be additionally configured to generate a notification about overheating 3 of the controlled element 2 and/or transmitting information about such overheating to another device when at least one sensor 5 detects products 4 released when heating 3 controlled elements 2 of electrical equipment or installed on them thermally activated gas-emitting materials 8, in a concentration above a given limit value, regardless of the current concentration of background gases recorded by other sensors 5.

In preferred embodiments, the claimed system additionally has a self-diagnosis function, informing about the need to replace the sensitive element of one or more sensors. The need to replace the sensing element may be due, in particular, to its degradation over time or the end of its specified service life.

Thus, taking into account the features of the system disclosed in the description, it is worth additionally noting that the content of both signal and background gases is recorded by sensors 5 by changing certain parameters of the gas-air environment, the values of which characterize the concentration of these gases, but do not determine its numerical absolute value. As mentioned above, comparison of parameters obtained from sensors is carried out depending on the system settings and, in the simplest case, can be a comparison of the difference in the values of these parameters with a given threshold value. In a more complex case, the concentrations of signal and background gases are compared with a threshold value using mathematical functions, and in the case of using several comparison sensors, the threshold value may not be set, and the parameters received from each sensor 5 will be analyzed by the controller 7 in dynamic mode by entering them or not falling into a set of values formed by the variance or standard deviation from the average value obtained from all or some sensors 5.

The system can use the following algorithms when generating a notification about overheating 3 of the controlled element 2 and/or transmitting information about such heating to another device:

- calculation of the running average value from each sensor for a given period of time;

- adjustment of the reference (zero) value;

- defining the reduced running average value as the difference between two running average values received from one sensor over two different periods of time, preferably a short period of less than one minute and a long period of more than 5 minutes;

- comparison of the given running average value with a threshold value and generation of an overheating notification if it is exceeded;

- determination of the average signal value received from different sensors by averaging the given running average values;

- comparison of the difference between the reduced running average values of signals from the comparison sensor and the monitoring sensor, including those calculated for different time periods, with a specified threshold value;

- determination of the growth rate of the reduced running average value and its comparison with the established threshold value;

- comparison of the signal received from the monitoring sensor with the set threshold value;

- determining the growth rate of the difference between the reduced running average value of the signal from the monitoring sensor and the comparison sensor and comparing it with the set threshold value;

- determination or change of threshold values based on the analysis of signal values received from sensors during operation;

- adaptive threshold

Let's look at them in more detail:

1. Calculation of the running average value from each sensor for a given period of time. In this case, the system generates a baseline against which the current concentration determined by sensors 5 is compared based on the running average concentration values determined by each sensor for a given period of time. The baseline can be obtained by averaging the running average data using a set of mathematical operations. The running average is calculated at each point in time using the formula:

Where - running average, x(t) - instantaneous signal value, T _ƒ - time for which averaging occurs, N - number of points over which averaging occurs.

2. Correction of the reference (zero) value. Due to the fact that each sensor 5, depending on external conditions and manufacturing features, may have slightly different sensitivity and aging rate, in order to maintain the original high sensitivity and accuracy of the system, the sensors used in it must be made with the ability to constantly smoothly take into account these features . Correction of the reference (zero) value, the drift of which occurs due to degradation of the sensing element, changes in temperature and humidity of the environment, as well as due to the possible presence of foreign gases in the atmosphere, is carried out in order to take into account slow processes that lead to changes in the characteristics of the sensor and are not obviously associated with the release of signal gas or products of thermal destruction of insulating materials. The reference value is adjusted by calculating the running average over a relatively long period of time, which is more than 5 minutes.

3. Definition of the reduced running average value as the difference between two running average values obtained from one sensor over two different periods of time. The system at each moment of time compares two main parameters with each other: a long running average (reference value) obtained from the gas sensor 5 over a time period, mainly more than 5 minutes, and characterizing the background concentration of gases, and a short running average obtained from this the same gas sensor over a period of time, preferably not exceeding 1 minute, and characterizing the current concentration of signal gases 4 in the controlled zone 1. A short running average makes it possible to smooth out signal fluctuations that occur over short time intervals and are associated with possible electromagnetic interference. The reduced running average is defined as the difference between two obtained values: short and long running averages.

4. Comparison of the given running average value with the threshold value and generation of an overheating notification if it is exceeded. Short and long running averages are calculated according to the algorithm given in paragraph 1. The given running average concentration is obtained using two values: short and long running averages - as a result of their difference or calculated using a more complex mathematical algorithm. An overheat notification is generated when the running average value exceeds a certain specified threshold value.

5. Determination of the average signal value received from different sensors by averaging the given running average values. The system determines short and long running average values according to the algorithm given in paragraph 1, however, when taking into account several sensors 5, the obtained data is averaged using a set of mathematical operations. To generate a notification about overheating, the average values are compared by calculating their difference or using more complex algorithms.

6. Comparison of the difference between the reduced running average values of signals from the comparison sensor and the monitoring sensor, including those calculated over different time periods, with a given threshold value. Short and long running average values are calculated for all sensors according to the algorithm given in paragraph 1. Data received from sensors 5 are taken into account to eliminate false positives. The comparison can be carried out over a certain period of time, the duration of which is determined experimentally and takes into account the delay in the entry and release of gas from controlled zone 1, which characterizes the degree of leakage of electrical equipment.

7. Determination of the growth rate of the reduced running average value and its comparison with the established threshold value. The reduced running average value is calculated similarly to the algorithm given in paragraph 3. The rate of increase of the reduced running average value of the signal gas concentration recorded by gas sensor 5, in the absence of overheating of the controlled elements, should be equal to zero. In the event of heating 3, leading to the release of products 4, for registration of which the gas sensor 5 is configured, the value of the rate of increase of the reduced running average will increase abruptly, which will lead to the generation of an overheating notification by the controller 7, even if the threshold concentration has not been reached.

8. Comparison of the signal received from the monitoring sensor with the set threshold value. The system can generate a notification about overheating 3 if one sensor 5 registers a sharp significant increase in the concentration of products 4 (exceeding the threshold value several times) released when heating 3 controlled elements 2 of electrical equipment or thermally activated gas-emitting materials 8 installed on them, and exceeding the established threshold values without taking into account the concentration of background gases determined by other sensors 5. For example, such a situation may arise when an electric arc burns or insulating materials ignite.

9. Determination of the growth rate of the difference between the reduced running average value of the signal of the monitoring sensor and the comparison sensor and its comparison with the set threshold value. The given running average values are calculated for all sensors 5 similarly to the algorithm given in paragraph 4. One of the criteria for generating an overheating notification is to compare the rate of increase of the reduced running average value of the signal gas content recorded by each sensor 5. When an external background source of signal gases occurs, the speed the increase in the reduced running average values G1 and G2, recorded by sensors S1 and S2, respectively, will be either equal (in the case of a low degree of tightness of the electrical installation or high diffusion of signal gases), or G1<G2 (if the electrical installation is sufficiently sealed and diffusion of foreign gases into the electrical installation occurs slowly) and the system will not operate. If G1>G2, then controller 7 will generate a notification about overheating 3, which will indicate a sharp increase in the concentration of signal gases 4 inside the electrical installation as a result of heating 3 controlled elements 2.

10. Determination or change of threshold values based on the values of signals received from sensors during operation. The system for automatically detecting overheating 3 of elements of electrical equipment 2 is made with the ability to determine and calibrate the maximum concentration of gases 4, which the sensors 5 are configured to detect, at which the system is triggered, using the method of testing the system according to the claimed group of inventions. Threshold values can be set by the controller 7 either manually when installing the system, or fixed in advance during the manufacture of the system, or be adaptive and dynamically changing depending on the operating conditions of the system.

11. Adaptive response threshold. During operation, the threshold value can be automatically adjusted in a specified range of values depending on the magnitude of fluctuations of foreign gases over a long period of time (more than 1 day). In such an algorithm, when the sensor is initially turned on, the threshold value is assumed to be equal to some initial value. Then, during a specified time interval, the maximum concentration value is recorded, which is recorded by a sensor or group of sensors, but which does not trigger the system. Based on the results of comparing the value of this maximum concentration with the threshold value, a decision is made to increase or decrease the threshold value.

Another criterion for the system to operate (generate a notification of overheating) is to compare the absolute values of the signals characterizing the content of products 4 released during heating of 3 controlled elements 2 or thermally activated gas-emitting materials 8 installed on them, and detected by two or more sensors 5. If C2 is the maximum value signal characterizing the content of background gases and registered S2 5 in the second controlled zone outside the first controlled zone 1 is equal to C1 - the value of the signal characterizing the content of the same gases in the first controlled zone and registered S1 5, then this will indicate an increase in the content of signal gases 4 due to the external background with a low degree of leakage of the protected area or high diffusion of these gases. The controller 7 will generate a notification about overheating 3 only if C1>C2, i.e. when the concentration of signal gases 4 inside one controlled zone 1 exceeds their background concentration in another controlled zone, outside the first controlled zone, which will indicate that the source of their occurrence is heated controlled elements 2. Likewise, the system will work if C2> C1, i.e. when S2 will act as a controlling sensor, and S1 as a comparison sensor.

In this case, the controller 7 can be configured in such a way as to compare the data received from the sensors 5 both in real time and with a certain time delay, determined experimentally and taking into account the delay in the entry and release of gas from the controlled zone 1, which characterizes the degree of leakage of electrical equipment .

The system may contain more than two sensors. Consider a system with n sensors. In this case, the minimum concentration of products 4, determined by one of the sensors S1 5, released during heating of 3 controlled elements 2, (C1), sufficient for the controller 7 to generate an overheating notification, may depend on the current concentration of background gases, determined by all other sensors Sn 5, either equally, or according to formula (1), taking into account the contribution of each comparison sensor separately:

where k _n are the gas distribution unevenness coefficients, determined experimentally for each of the n sensors, taking into account the characteristics of their locations, for example, depending on the degree of leakage of the controlled electrical equipment 1 or on the distance of the sensor Sn from the sensor S1. In the vast majority of cases, k lies within [0;1], preferably selected from the group: 0; 0.5; 1. Thus, depending on the system settings, the signals received by the controller 7 from individual sensors Sn can either be fully taken into account (k=1), or partially taken into account, or completely ignored (k=0). In particular, the system can be configured in such a way that the controller does not take into account the extreme values of the background gas concentrations detected by the sensors, i.e. in this case, the coefficient k will not be fixed and can take a zero value depending on the data received from the sensors.

To test this system, the following method can be implemented, including the following steps:

- installation of S1 in the first gas chamber and installation of S2 in the second gas chamber, connecting the controller to the specified sensors;

- registration of the fact of operation of the system in the absence of influence of model gases on S2 by heating the model element in the first chamber and/or determining threshold concentrations by dosing model gas at a given concentration into the first chamber;

- registration of the fact that the system does not operate when dosing model gas into both chambers

and/or

determination of threshold concentrations by separate dosing of model gas into both chambers.

Heating the model element may include heating the thermally activated material in the first gas chamber.

Testing the system in this manner provides a clear, regulated check of the system’s compliance with the conditions and algorithms described in the first object of the claimed group of inventions, as well as for its further use in identifying overheating of electrical equipment elements.

The implementation of the method in particular cases can be presented as follows: one sensor 5 (Fig. 3a) is placed in the first gas chamber 9 filled with a neutral gas, which can be used, for example, nitrogen, and the other sensor 5 is placed in the second gas chamber chamber 9 filled with the same neutral gas. Both sensors are connected to the controller 7, in particular, by wired connection 10, and record the absence of operation of the system in this state. Then, a model gas simulating a signal gas is dosed into the first gas chamber 9, and the minimum concentration of this model gas is recorded, at which the system is triggered and the controller generates an overheating notification, thereby determining the threshold value.

After the installation for testing the system is returned to its original state, a model gas simulating a signal gas is dosed in a known concentration of C2, not exceeding the threshold concentration at which the system can operate, into the second gas chamber 9 and the absence of system activation is recorded. Then the same model gas is dosed into the first gas chamber in a concentration not exceeding C2, and the absence of operation of the system is recorded. With a further gradual increase in the content of the model gas in the first chamber 9, the minimum gas concentration is recorded at which the system is triggered and the controller generates a notification about overheating. Using the obtained value, the threshold gas concentration is calculated at which the system operates.

In another embodiment of the method of testing a system according to the stated group of inventions, a heating element 2 is installed in the first gas chamber 9, filled with neutral gas, and in the second gas chamber 9, filled with the same neutral gas, a controlled heating element 2 is installed, on which the TGM 8 is located (used in this case as a product containing THM) (Fig. 3b). Both sensors are connected to the controller 7 via a wire connection 10 and record the absence of operation of the system in this state. Then the heating element 2, installed in the second gas chamber 9, is heated to the activation temperature of the gas-emitting sticker 8 and the operation of the system is recorded by registering an overheating notification issued by the controller 7, informing about the overheating of electrical equipment elements. After the installation for testing the system is returned to its original state, a model gas simulating a signal gas is dosed into both gas chambers 9 in a known concentration not exceeding the threshold concentration at which the system can operate, and the absence of system activation is recorded. Then the heating element 2, located in the first gas chamber, is heated until the products of thermal destruction of the polymer insulation 4 begin to release and the operation of the system is recorded by registering an overheating notification issued by the controller 7, informing about the overheating of 3 elements of electrical equipment 2.

According to the claimed group of inventions, a system for automatically detecting overheating of electrical equipment elements is used in accordance with the following method:

- placement of the system according to the first option, in which

at least one gas sensor S1 is installed in one controlled area and gas sensor S2 is installed in another controlled area;

the controller is installed in an arbitrary location and communicates with at least two gas sensors, including at least S1 and S2, by wired or wireless communication;

- processing of an overheating notification generated by the controller with subsequent issuance of an information message and/or transfer of data to another device connected to the controller.

The method may also implement algorithms, in particular those disclosed in this application when describing the system. In particular, with the additional presence of at least one comparison sensor 6, the controller 7 can additionally generate a notification about overheating when one of the sensors detects gases 4 released when heating 3 controlled elements 2 or thermally activated gas-emitting materials 8 installed on it, in a concentration above a specified limit values regardless of the background gas content detected by at least one other sensor 5 or one other comparison sensor 6.

In the preferred embodiment, the detection of overheating 3 of the controlled elements 2 of electrical equipment occurs through the registration of signal gases 4 released from thermally activated gas-emitting materials 8 of predominantly reusable action, included in the products or coatings installed or applied to the controlled elements 2 of electrical equipment.

Let us consider special cases of implementation of the specified claimed group of inventions.

Examples.

Example 1.

The system according to the claimed group of inventions is installed as follows: one semiconductor sensor S1 is placed in the first sealed gas chamber with a volume of 100 liters, filled with nitrogen, and containing a heating element coated with an insulating material. The second semiconductor sensor S2 is placed in a second sealed gas chamber with a volume of 100 L, filled with nitrogen, also containing a heating element covered with insulating material. Both sensors are connected to the controller via wired communication and record the absence of system operation in this state. Then the heating element is heated to a temperature of 100°C, at which thermal destruction of the insulating materials begins, but no fire occurs. The operation of the system is recorded by registering a notification issued by the controller informing about overheating of electrical equipment elements. In this example, the system is activated due to the detection by one of the sensors (S1) of gases released as a result of heating of the model element, in the absence of influence of background gases on S2.

Example 2.

The system according to the claimed group of inventions is installed as follows: one semiconductor sensor S1 is placed in the first sealed gas chamber with a volume of 100 l, filled with nitrogen. The second semiconductor sensor S2 is placed in a second sealed gas chamber with a volume of 100 L, filled with nitrogen. Both sensors are connected to the controller via wired communication and record the absence of system operation in this state. Then, a model gas simulating signal gases is dosed into the first gas chamber in a continuous mode at a rate of 10 ppm/min. The system does not operate within the first five minutes (with signal gas content up to 50 ppm). The operation of the system is recorded at the fifth minute by registering a notification issued by the controller informing about overheating of electrical equipment elements, and the content of model gas in the first chamber at this moment is determined. The test is repeated three times, determining the average threshold concentration, which in this example was 54 ppm. In this example, the system is triggered due to the detection of model gases by one of the sensors (S1), simulating gases released as a result of heating of the model element, in the absence of influence of background gases on S2.

Example 3.

The system according to the claimed group of inventions is installed as follows: one semiconductor sensor S1 is placed in the first sealed gas chamber with a volume of 100 l, filled with nitrogen. The second semiconductor sensor S2 is placed in a second sealed gas chamber with a volume of 100 L, filled with nitrogen. Both sensors are connected to the controller via wired communication and record the absence of system operation in this state. Then, into the second gas chamber in which S2 is installed, a model gas simulating the signal gas is dosed simultaneously in the amount of C2 = 100 ppm. The operation of the system is recorded by registering a notification issued by the controller. In this case, the system is triggered due to the detection by one of the sensors (S2) of model gases simulating signal gases in a concentration exceeding a threshold value, regardless of the concentration of background gases recorded by S1.

After this, a model gas simulating the signal gas (C1) is dosed into the chamber in which S1 is installed, in continuous mode at a speed of 10 ppm/min. The absence of system activation is recorded in the first 15 minutes, when the content of model gases in the first chamber did not exceed 150 ppm. After the content of model gases in the first chamber reaches 150 ppm, the operation of the system is recorded by registering a notification issued by the controller. This determines the threshold concentration for the system to operate, which in this case is equal to 50 ppm. In this case, the system is triggered due to the detection by one of the sensors (S1) of model gases simulating signal gases, taking into account the content of the same model gases recorded by S2.

Next, in order for the system to exit the operation mode, the gas chambers are ventilated and refilled with nitrogen, after which they begin to continuously dose the model gas, simulating the signal gas, at a rate of 50 ppm/hour until its actual content is reached, equal to 100 ppm. The change in the reference (zero) value of the sensor signal is recorded due to the system implementing zero value drift algorithms at a low rate of increase in the signal gas concentration. Then, 50 ppm of a model gas simulating the signal gas is simultaneously dosed into the first gas chamber, while the actual content of this gas in the first chamber was 150 ppm. The operation of the system is recorded by registering a notification issued by the controller. In this case, the possibility of repeated operation of the system is realized.

Example 4.

The system according to the claimed group of inventions is installed as follows: one optical sensor S1 is placed in the first sealed gas chamber with a volume of 100 liters, filled with nitrogen, and containing a heating element on which a thermally activated gas-emitting sticker with an activation temperature of 100°C is placed. The second optical sensor S2 is placed in a second sealed gas chamber with a volume of 100 liters, filled with nitrogen, also containing a heating element with a thermally activated gas-emitting sticker placed on it. Both sensors are connected to the controller via wireless communication and record that the system does not operate in this state. Then the heating element in the first chamber is heated to a temperature of 100°C, at which thermal activation of the sticker begins and signal gases are released from it. The operation of the system is recorded by registering a notification issued by the controller informing about overheating of electrical equipment elements. In this case, the system is activated due to the detection by one of the sensors (S1) of gases released during the activation of a thermally activated gas-emitting material, in the absence of influence of background gases on S2.

Next, the gas chamber is ventilated so that the system exits the operation mode, it is refilled with nitrogen, and the heating element is cooled to room temperature. After this, the heating element is again heated to a temperature of 100°C and the operation of the system is recorded. In this case, the possibility of repeated operation of the system when using thermally activated gas-emitting materials is realized.

Example 5.

The system according to the claimed group of inventions is installed as follows: one semiconductor sensor S1 is placed in the first sealed gas chamber with a volume of 100 liters, filled with nitrogen, and containing a heating element coated with an insulating material. The second semiconductor sensor S2 is placed in a second sealed gas chamber with a volume of 100 L, filled with nitrogen, also containing a heating element covered with insulating material. Both sensors are connected to the controller via wired communication and record the absence of system operation in this state. Then, 500 ppm of model gas, simulating the background gas, is dosed into both chambers for 10 hours at a rate of 50 ppm per hour. The absence of system activation is recorded due to the system implementing an algorithm that takes into account the drift of the zero value. After this, the heating element installed in the first chamber containing S1 is heated to a temperature of 200°C, at which thermal destruction of the insulating materials occurs, but fire does not occur. The operation of the system is recorded by registering a notification issued by the controller informing about overheating of electrical equipment elements. In this example, the system is triggered due to the detection by one of the sensors (S1) of gases released as a result of heating of the model element, under the influence of background gases on both sensors, taking into account the drift of the zero value.

Example 6.

The system according to the claimed group of inventions is installed as follows: one semiconductor sensor S1 is placed in the first sealed gas chamber with a volume of 100 l, filled with nitrogen. The second semiconductor sensor S2 is placed in a second sealed gas chamber with a volume of 100 L, filled with nitrogen. Both sensors are connected to the controller via wired communication and record the absence of system operation in this state. Then, 500 ppm model gas, simulating a signal gas, is dosed into both gas chambers simultaneously for 10 hours at a rate of 50 ppm per hour. The absence of system activation is recorded due to the system implementing an algorithm that takes into account the rate of increase in the concentration of the signal gas. After this, a model gas simulating a signal gas in an amount of 50 ppm is simultaneously introduced into the first chamber containing S1. The operation of the system is recorded by registering a notification issued by the controller informing about overheating of electrical equipment elements. In this example, the system is triggered by detecting S1 of a model gas simulating a signal gas, under conditions of a rapid increase in its concentration and taking into account its influence on S2.

Example 7.

The system according to the claimed group of inventions, which includes two monitoring sensors and one comparison sensor, is installed as follows: each monitoring semiconductor sensor S1 and S2 is placed in a separate sealed gas chamber with a volume of 100 liters, filled with nitrogen. The semiconductor reference sensor S _cp is also placed in a separate sealed gas chamber with a volume of 100 l, filled with nitrogen. All sensors are connected to the controller via wired communication and record the absence of system operation in this state. The controller is configured to take into account the content of background gases recorded by each of the sensors, including the comparison sensor, to an equal extent. All gas chambers are simultaneously dosed with 500 ppm of model gas, simulating a signal gas. The operation of the system is recorded by registering a notification issued by the controller informing about overheating of electrical equipment elements. In this example, the system is activated due to the detection by the monitoring sensors S1 and S2 and the comparison sensor S _cp of a model gas simulating a signal gas under conditions of a rapid increase in its concentration.

Example 8.

The system according to the claimed group of inventions, including three comparison sensors and three control sensors, is installed as follows: each of the semiconductor sensors S _k is placed in a separate sealed gas chamber with a volume of 100 l, filled with nitrogen. Each of the S _cp semiconductor sensors is placed in a separate sealed gas chamber with a volume of 100 L, filled with nitrogen. All sensors are connected to the controller via wired communication and record the absence of system operation in this state. The controller is configured to take into account the content of background gases recorded by each of the comparison sensors, according to formula (1), which takes into account the contribution of each comparison sensor separately.

Let's consider one of the controlling sensors (S _to 1), for which the following formula (2) will be valid:

where C _to 1 is the maximum detected S _to 1 value of the content of products released during heating of the controlled elements, sufficient for the system to operate, C _cp 1-C _av 3 - values of the background gas content detected by comparison sensors S _cp 1-S _cp 3, respectively , k ₁ -k ₃ - gas distribution unevenness coefficients, determined experimentally for each comparison sensor. In this case: k ₁ =1, k ₂ =0.5, k ₃ =0.

A model gas simulating the background gas is continuously dosed into all gas chambers containing reference sensors at a rate of 50 ppm/min until its content in each chamber is achieved, presented in Table 1. Then, according to formula (2) C _to 1=(1*250 +0.5*1000+0*1500)/3=250 ppm.

At the same time, a model gas simulating a signal gas is continuously dosed into the first gas chamber containing S _to 1 at a rate of 50 ppm/min. In the first 5 minutes of dosing, until the model gas content in this gas chamber reaches 300 ppm, the absence of system activation is recorded by taking into account the concentrations of foreign gases measured by comparison sensors. With further dosing and the content of the model gas simulating the signal gas reaches more than 300 ppm in the first gas chamber, the operation of the system is recorded by recording the signal issued by the controller, informing about the heating of electrical equipment elements.

In this example, the system is triggered due to the detection by the monitoring sensor of a model gas simulating a signal gas, under the influence of background gases on the comparison sensors, taking into account the different contribution of each comparison sensor.

Example 9.

An example of the implementation of algorithms for processing concentrations measured by sensors by the controller and generating a notification about overheating in the system according to the claimed group of inventions, including one or more monitoring sensors and one comparison sensor connected to the controller.

Initial signal averaging:

To filter possible instantaneous signal jumps that may be associated with induced electromagnetic interference, it is quickly averaged. Signal used for further analysis is calculated as a result of averaging over T _ƒ seconds (running average), over N values of the instantaneous signal x(t).

Adjustment of the reference (zero) signal level:

The reference (zero) value of the signal is constantly subject to smooth adjustment, as it changes over time (drifts) due to degradation of the sensitive element, changes in temperature and humidity of the environment, and also due to the possible presence of foreign gases in the atmosphere.

The average value of the absolute value of the characteristic measured by the sensor is taken as the zero value of Z(t) for the last T _d minutes. If the signal value falls below the zero value, then the zero value becomes equal to

In this case, the relative value of concentration in arbitrary units will be equal at each moment of time:

Constant threshold:

A notification about overheating of monitored elements (transition to alarm mode) is generated by default when the concentration threshold value is exceeded.

X(t)>P _i

Depending on the controller sensitivity level setting, the threshold gas concentration changes:

At low (LF mode) sensitivity P ₁

At medium (mid mode) sensitivity P ₂

At high (HF mode) sensitivity P ₃

The alarm mode is exited when the sensor concentration drops below half the corresponding threshold value.

Floating threshold:

In this mode, the threshold value P is adjusted depending on the magnitude of fluctuations of external gases. When the sensor is turned on, the threshold value is assumed constant and equal to P=P ₂ (average sensitivity). Within T _ƒ days (1 day or more), the maximum value of the signal S _{max is recorded.} , which does not lead to the formation of an alarm signal (that is, does not exceed the current threshold value) If this value is less than the current threshold by K times (for example, K = 3), then the threshold is reduced by 1.1 times. If this condition is not met, then the threshold is increased by 1.1 times.

The threshold change can only occur in the range between P ₁ and P ₃ . When the floating threshold value P ₃ is exceeded, it is assumed to be equal to P ₃ . When the floating threshold is lowered below the value P _{1 ,} it is assumed to be equal to P ₁ .

Algorithm for taking into account the signal measured by the comparison sensor:

The comparison sensor is installed in a place where the probability of an increase in the concentration of the signal gas or thermal degradation products of insulation will be minimal and serves to detect false alarms.

To take into account possible delays in gas propagation, the concentrations of the reference sensor are taken into account as follows. During the time T _ext , the maximum concentration value measured by the comparison sensor is determined:

for T _ext < T ≤ t

The operation of the monitoring sensor will be interpreted as false if, during the transition of generating a notification about the heating of the controlled elements, the following condition is met:

Generating a fire or fire notification:

The internal gas sensors are triggered, regardless of the concentrations recorded by the external sensor or neighboring internal sensors, when the following condition is met:

X(t) > P _ƒire

where P _ƒire is the threshold value of gas concentration, which indicates the possible occurrence of a fire.

Tables 2-4 present possible settings for the controller that implements the considered example of mathematical algorithms.

The results of the tests prove the implementation of the stated purpose of the system and methods for the declared group of inventions and the achievement of a technical result.

The group of inventions was disclosed above with reference to a specific embodiment. For specialists, other embodiments of the claimed group of inventions may be obvious, without changing its essence, as it is disclosed in this description. Accordingly, the group of inventions should be considered not limited in scope by the given description and examples.

Claims (49)

1. System for automatic detection of overheating of electrical equipment elements, including: - at least two gas sensors (S1, S2), designed for installation in at least two different controlled zones (V1 and V2, respectively) to detect gases released when the controlled element or thermally activated gas-emitting materials installed on it overheat; - a controller configured to connect with at least two gas sensors S1 and S2 and generate a notification about overheating and/or transmit information about such overheating to an external receiving device when the sensor S1 detects gases released during overheating of the controlled element or installed on it thermally activated gas-emitting materials in the controlled zone V1, taking into account the difference in the concentrations of these gases in the controlled zones V1 and V2, as well as when sensor S2 detects gases released when the controlled element or thermally activated gas-emitting materials installed on it are overheated in the controlled zone V2, taking into account the difference in the concentrations of these gases in the controlled zones V1 and V2. 2. The system according to claim 1, in which the sensors are semiconductor type sensors, the sensitive element of which is designed to detect gases released when insulating materials overheat, including, in particular, cross-linked polyethylene (PE), polyvinyl chloride (PVC), rubber, silicone , epoxy resin. 3. The system according to claim 1, characterized in that S1 and S2 are designed to detect gases released when heating thermally activated gas-emitting stickers installed on the controlled elements. 4. The system according to claim 1, characterized in that it additionally includes thermally activated gas-emitting materials of predominantly reusable action, included in the composition of products or coatings installed or applied to the controlled elements. 5. The system according to claim 1, characterized in that S1 and S2 have a sensitive element of the same type and are designed to detect gases belonging to classes of compounds selected from the list: halocarbons, hydrogen halides, halohydrocarbons, alkenes, alkanes, mercaptans, acids or mixtures thereof, preferably gases selected from the list: carbon tetrafluoride, tetrafluoroethylene, tetrachlorethylene, trifluorochloromethane, chloroform, dichloromethane, methyl chloride, methyl bromide, trifluoromethane, ethyl chloride, vinyl chloride, hydrogen fluoride, hydrogen chloride, ethylene, propylene, butadiene, isoprene, methane, ethane, butane, hexane, methyl mercaptan, dimethyl sulfide, ethyl mercaptan, diethyl sulfide, nitric acid, nitrous acid, or mixtures thereof. 6. The system according to claim 1, characterized in that the controller is configured to generate a notification when sensor S1 detects gases released when the controlled elements overheat in a concentration above a specified limit value, regardless of the current concentration of background gases detected by sensor S2. 7. The system according to claim 1, characterized in that it contains more than two sensors, and the formation of a notification by the controller takes into account the average concentrations of gases received from various sensors, with the same or different contribution from each individual sensor. 8. The system according to claim 1, characterized in that it is designed to detect overheating of contacts and contact connections of closed electrical equipment, including contact connections of electrical panels, complete switchgears, low-voltage complete devices, distribution block boxes and windings. 9. The system according to claim 1, characterized in that the sensors S1 and S2 are designed to be installed in different places of one section of electrical equipment in such a way that the gas released from the controlled element is preferably captured by one of the sensors. 10. The system according to claim 1, characterized in that it is designed to detect overheating of insulating materials of electrical equipment elements, including cable couplings. 11. The system according to claim 1, characterized in that it is designed to prevent fires in electrical equipment. 12. The system according to claim 1, characterized in that it additionally has a self-diagnosis function that informs about the need to replace the sensitive element of one or more sensors. 13. The system according to claim 1, characterized in that the system is additionally equipped with one or more temperature sensors. 14. The system according to claim 1, characterized in that it additionally contains a comparison sensor connected to the controller and installed outside the controlled areas, but close to them, and designed to detect background gases in the air. 15. The system according to claim 1, characterized in that the controller uses one or more of the following algorithms to process signals received from gas sensors: - zero value adjustment; - calculation of the running average value from each sensor for a given period of time; - defining the reduced running average value as the difference between two running average values received from one sensor over two different periods of time, preferably a short period of less than one minute and a long period of more than 5 minutes; - comparison of the given running average value with a threshold value and generation of an alarm if it is exceeded; - determination of the average signal value received from different sensors by averaging the given running average values; - comparison of the difference between the reduced running average values of signals from various sensors, including those calculated over different time periods, with a given threshold value; - determination of the growth rate of the reduced running average value and its comparison with the established threshold value; - comparison of the sensor signal with the set threshold value; - determining the growth rate of the difference in the reduced running average value of the sensor signal and comparing it with the set threshold value; - determination or change of threshold values based on the analysis of signal values received from sensors during operation; - adaptive response threshold. 16. The system according to claim 1, characterized in that the controller is configured to generate a notification about overheating of the controlled element and/or transmit information about such overheating to an external receiving device when the sensors detect gases released when the controlled element overheats in a concentration exceeding the threshold a value that takes into account the content of background or other gases that affected these sensors during the previous period of time. 17. Method of testing the system according to claim 1, including the following steps: - installation of S1 in the first gas chamber and installation of S2 in the second gas chamber, connecting the controller to the specified sensors; - checking the fact of operation of the system, based on the formation of an overheating notification by the controller, in the absence of influence of model gases on S2 by heating the model element in the first chamber or by dosing model gas into the first chamber; - checking the fact that the system does not operate, based on the fact that the controller does not generate an overheating notification, while simultaneously dosing model gas into both chambers. 18. The method according to independent claim 17, wherein heating the model element includes heating a thermally activated gas-emitting material in the first gas chamber. 19. Method of testing the system according to claim 1, including the following steps: - installation of S1 in the first gas chamber and installation of S2 in the second gas chamber, connecting the controller to the specified sensors; - determination of threshold concentrations of gases corresponding to the operation of the system, based on the absence of the controller generating an overheating notification, by dosing model gas in a given concentration into the first chamber and/or - determination of threshold concentrations of gases corresponding to the operation of the system, based on the formation of an overheating notification by the controller, by separately dosing model gas into both chambers. 20. A method for automatically detecting overheating of electrical equipment elements, including - placement of the system according to claim 1, in which at least one gas sensor S1 is installed in the controlled area V1 and gas sensor S2 is installed in the controlled area V2, and the controller is installed in an arbitrary location and communicates with at least two gas sensors, including at least S1 and S2, by wired or wireless communication; - processing of a notification about overheating generated by the controller with subsequent issuance of an information message and/or transmission of data to an external receiving device associated with the controller, taking into account the difference in gas concentrations in the controlled zones V1 and V2. 21. The method according to claim 20, characterized in that it is intended to detect overheating of contacts and contact connections of closed electrical equipment, including contact connections of electrical panels, complete switchgears, low-voltage complete devices, distribution unit boxes and windings. 22. The method according to claim 20, characterized in that it is intended to detect overheating of insulating materials of electrical equipment elements, including cable couplings. 23. The method according to claim 20, characterized in that it is intended to prevent fires in electrical equipment. 24. The method according to claim 20, characterized in that it is intended to detect defects in insulating materials of electrical equipment elements resulting from the passage of arc discharges. 25. The method according to claim 20, characterized in that the controller can also generate a notification about overheating when one of the sensors detects gases released when the controlled elements overheat in a concentration above a specified limit value, regardless of the content of background gases detected by at least one another sensor. 26. The method according to claim 20, characterized in that it is intended to detect overheating using thermally activated gas-emitting materials, mainly of repeated action, included in the composition of products or coatings installed or applied to the controlled elements.