KR20100049216A - Method for detecting arc in power distribution system and system for alerting arc using the same method - Google Patents

Abstract

PURPOSE: A method for detecting arc in a power distribution system and a system for alerting arc using the same method are provided to prevent an electrical fire by monitoring an arc in the power distribution system and generating a trip signal when abnormal arcs occurs. CONSTITUTION: A sensor(10) detects an arc. A signal conditioning unit(20) receives a current signal outputted from a sensor and divides an arc component. A central processor(30) calculates the number and width of a pulse of an arc outputted from the signal conditioning unit at period and classifies the state of arc based on the calculation result. An alarm output unit(40) generates a trip signal and an alarm signal by the control of the central processing unit.

Description

Method for Detecting Arc In Power Distribution System And System For Alerting Arc Using The Same Method}

TECHNICAL FIELD The present invention relates to an arc detection method and an arc generation alarm system, and in particular, monitors an arc generation state in a power distribution system, alarms when an abnormal arc occurs, generates a trip signal, and saves human life and property from an electric fire. The present invention relates to an arc detection method in a power distribution system for protecting an arc and an arc generation alarm system using the same.

Arcs in low-voltage power distribution systems cause heat to the wire sheaths and contact surfaces, which in turn causes fires. Recent data show that about 80% of all fires are caused by arcing.

Today's low-voltage distribution systems are protected by overcurrent protection circuit breakers that detect overloads and short circuits and earth leakage breakers that detect ground faults. If such protective relays are applied properly, other forms of circuit protection may be recognized as not necessary. However, electrical arcing cannot be prevented with these protective relays.

A common beginning of arc generation is the spark phenomenon across organic insulators. The arcing surface is carbonized or pyrolyzed, causing the electrical conductors to generate larger arcs, eventually leading to a fire when the accumulated heat exceeds the ignition point. As such, an arc alarm and a trip signal generator are required to prevent a fire caused by an arc that cannot be blocked by an existing protective relay.

On the other hand, the arc can also occur when opening and closing the electromechanical apparatus. It is even occurring in normal operation in some electrical appliances. In other words, the charging current generated when using a rectifier using a switching surge and a large capacity capacitor generated during ON / OFF also has an arc component. Therefore, if the arcs generated during the normal operation and the abnormal arcs occurring in the failure state such as insulation breakdown, line short circuit, ground fault, etc. of the wires are not clearly distinguished, unwanted interruption or alarm may occur.

Conventionally, the biggest problem in detecting and alarming the occurrence of the arc was to recognize the arcing phenomenon caused by the use of a normal electric machine as described above as a failure state to issue an arc alarm.

In order to solve the above problems, a method of determining the state of the arc by comparing the load current before and after the arcing phenomenon has been disclosed Patent Registration No. 10-0122576, 'Electric fire symptom warning device and method'. The patent recognizes arcing phenomena due to starting or stopping the use of electrical appliances when the load current increases or decreases after the arc / spark occurs. In other words, if there is a change in the load current before or after the arc / spark occurrence, it is recognized as an arcing phenomenon due to the use of electrical appliances. If there is no change in the load current, it is recognized as an electrical fire symptom.

However, in the above patent, in order to determine whether the load current fluctuates, the average value of the load current passing through the wire before and after the arc / spark occurrence must be calculated and compared. Therefore, a load that is used in case of minute load fluctuations and frequent starting stops is used. In this case, and rapidly progressing arc phenomenon is not detectable problem.

In order to solve the above problems, techniques described in the following patent documents have been proposed.

Chun-Yeon Kim et al. In Korean Patent Application No. 10-2000-0048580, 'Circuit Breaker and Implementation Method for Electronic Trip' converts the current change flowing through the AC power into voltage, extracts high frequency components, and then After filtering, the integrated circuit breaker and its implementation method generate an abnormal signal when the value is over the set value.

In addition, Kim Cheon-Yeon et al. Proposed an arc defect protection circuit and circuit breaker for detecting arc defects in a power distribution system similar to the patent in Patent Application No. 10-2001-0022392, 'Arc fault protection circuit breaker and circuit breaker having the same'. It was. In the above application, in order to remove noise of the output voltage of the current detector, a method of removing a high frequency component and limiting it to a specific frequency range is used.

Siemens Braid et al., Patent No. 10-0378629, "Arking detection method and apparatus in the AC power system by high frequency noise monitoring" to monitor the power waveform for broadband high frequency noise in the AC power system, and to the power waveform A method of detecting arcing phenomenon has been proposed by testing the detected noise against a synchronized pattern of change in its amplitude.

The patent detects an arc detected by sweeping the detection bandwidth using a voltage-variable-capacitance tuning diode or the like which forms a tank circuit tuned with a transducer coil to detect the frequency band of generated arc noise. It is confirmed whether noise occurs over a wide band, and if the arc noise is a wide band, it is determined as an arc phenomenon. In addition, it is possible to confirm various arcing detection-related technologies filed or registered in the United States through the references described in the patent document.

The present invention, unlike the arc detection related technologies according to the prior art introduced above, by separating the current signal and the voltage signal to convert the voltage signal equal to the phase of the current signal into a frequency component, the basic of the current signal The arc detection method in the distribution system that can detect the occurrence of abnormal arc by comparing the pulse characteristic of the input arc component with the pulse characteristic of the previous section by receiving the remaining arc component except the frequency component, and the arc generation alarm system using the same For the purpose of providing, the arc detection method and the arc generation alarm system according to the invention are not disclosed in any of the above documents.

Accordingly, an object of the present invention is to provide an arc detection method in a power distribution system that can detect an arc through a current signal of a power distribution line by supplementing and improving the aforementioned various problems.

Another object of the present invention is to provide an arc detection method in a distribution system that can separate a current signal of a distribution line into a load current signal and an arc noise signal.

In addition, another object of the present invention is to provide an arc detection method in a distribution system that can read the input arc pulse number and pulse width per cycle of the arc noise signal separated from the current signal of the distribution line through a digital signal processor (DSP). To provide.

In addition, another object of the present invention is to analyze the number of arc pulses and the pulse width input per cycle read through the DSP and to recognize the fault state if the pulse input number increases rapidly and the width is random compared to the state of the previous section. The present invention provides an arc generation alarm system in a power distribution system that can alarm.

An arc detection method for detecting an arc in a power distribution system according to the present invention for achieving the above objects and determining whether it is a normal arc or an arc in a fault state and generating an alarm and a trip signal includes an electric signal in the power distribution system. Separate detection into a current signal and a voltage signal; Converting a voltage signal of the same phase as the current signal into a frequency component; Extracting the remaining arc component except the fundamental frequency component of the current signal; Recognizing arc generation by the number of pulses and the width of the pulse input per one period of the extracted arc component;

Arc generation alarm using the arc detection method in the power distribution system to detect the arc in the low-voltage power distribution system according to the present invention for achieving the above objects to determine whether it is a normal arc or a faulted arc and to generate an alarm and a trip signal The system includes a sensor unit for arc detection; A signal conditioning unit for separating an arc component by receiving a current signal output from the sensor unit; A central processing unit for calculating the number and width of pulses input per cycle of the arc input from the signal conditioning unit and distinguishing between normal arcs and abnormal arcs based on this; And an alarm output unit configured to generate a trip signal and an arc generation alarm under the control of the central processing unit.

As described above, the present invention distinguishes the current signal from the voltage signal, converts a voltage signal equal to the phase of the current signal into a frequency component, and receives an arc component other than the fundamental frequency component of the current signal, thereby receiving the current. By separately separating the load current signal and the arc noise signal from the signal, and clearly distinguishing the abnormal arc from the arc noise signal, there is an effect that the alarm can be alarmed only when an abnormal arc occurs without an unwanted interruption or alarm.

In addition, the present invention can provide an arc generation alarm system having a simple structure and fast operation speed by determining the abnormal arc using a DSP.

Accordingly, the present invention has an effect that can be an early warning for the abnormal arc.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a detailed description of preferred embodiments of the present invention will be given with reference to the accompanying drawings. It should be noted that the same components in the figures represent the same numerals wherever possible. Specific details are set forth in the following description, which is provided to provide a more thorough understanding of the present invention. In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

The present invention, unlike the arc detection related technologies according to the prior art introduced above, by separating the current signal and the voltage signal to convert the voltage signal equal to the phase of the current signal into a frequency component, the basic of the current signal Receives the arc component except frequency component, reads and analyzes the input arc pulse number and pulse width per cycle of the input arc component, compares it with the state of the previous section, and if the pulse input number increases rapidly and the width is random Provided are an arc detection method in a power distribution system that can alarm occurrence of abnormal arcs, and an arc generation alarm system using the same.

The present invention receives the current signal through the current sensor of the distribution line in the low-voltage distribution system, converts it into a voltage signal and separates the load current for calculation and arc measurement. The load current calculation is rectified and then amplified and smoothed and applied to the A / D input port of a digital signal processor (DSP). The central processing unit reads the input load current and transmits the current magnitude of the load to an external monitoring system.

The arc measurement signal detects harmonic components other than a fundamental component of 60 Hz through a high pass filter, and only a pulse signal above the reference voltage is applied to the counter input port of the DSP through a comparator.

The DSP counts the number of input harmonic pulses, measures the width, and stores the width in the memory. The DSP analyzes the input signal and analyzes the number of arc pulses and pulse widths inputted per cycle, and compares the state of the previous several sections with a sudden increase in the number of pulse inputs and recognizes a fault condition if the width is random. . In addition, the DSP generates an alarm signal when the incoming arc is recognized as an arc in a fault state.

Hereinafter, with reference to the drawings will be described an embodiment according to the present invention in more detail. The arc generation alarm system of the present invention detects the remaining arc component except the fundamental frequency component (60 Hz) of the current signal input through the current sensor and recognizes the arc generation by the number of pulses input and the width of the pulse per frequency.

1 is a block diagram of an arc generating alarm system according to a preferred embodiment of the present invention, as shown in the arc generating alarm system according to the present invention, the sensor unit 10, the signal conditioning unit 20, the central processing unit ( 30) and an alarm output unit 40.

The sensor unit 10 receives the three-phase voltage and current of the power distribution system to the voltage sensor circuit and the current sensor circuit for arc detection, and applies them to the signaling conditioning unit 20, respectively. The voltage sensor circuit and the current sensor circuit are shown in detail below in the embodiments of FIGS. 2 and 3, respectively.

The signal conditioning unit 20 receives a current signal output from the sensor unit 10 and a current signal processing unit for processing a current signal applied from the current sensor circuit of the sensor unit 10 to separate the arc component; A power supply voltage frequency signal detection unit for processing a voltage signal applied from a voltage sensor circuit of the sensor unit 10 to separate a frequency component of a voltage having the same phase as the current signal, and output from the sensor unit 10. It consists of a load current processing unit that processes the current signal applied from the current sensor circuit of the sensor unit 10 for outputting to the central processing unit 30 for calculating the load current by rectifying the current signal, rectified and then amplified and smoothed. do. The current signal processor, the power supply voltage frequency signal detector, and the load current processor are described in detail below with reference to FIGS. 4 to 6.

The central processing unit 30 calculates the number and width of the input pulses per cycle of the arc input from the signal conditioning unit 20 and distinguishes whether it is a normal arc or an abnormal arc. The central processing unit 30 according to the present invention is implemented as a DSP, and an embodiment thereof is shown in detail in FIG. 7.

The alarm output unit 40 generates a trip signal and an arc generation alarm under the control of the central processing unit 30. Like the central processing unit 30, an embodiment thereof is shown in detail in FIG.

First, referring to FIG. 2 and FIG. 3, the voltage sensor circuit and the current sensor circuit according to the present invention will be described. As shown in FIG. 2, the voltage sensor circuit of FIG. 2 respectively uses three-phase input voltages S1_VR, S1_VS, and S1_VT. It receives the input and outputs output voltages V1, V2, and V3, respectively. The output voltages V1, V2, V3 of the voltage sensor circuit are input to the power supply voltage frequency signal detector shown in FIG. 5 described below. Since the electrical signal of the power distribution system generally used is a three-phase signal, the following description will be based on this.

The current sensor circuit of FIG. 3 receives three-phase input currents and outputs output currents CT_IN1, CT_IN2, and CT_IN3, respectively. The output currents CT_IN1, CT_IN2, and CT_IN3 of the current sensor circuit are branched and input to the current signal processor shown in FIG. 4 and the load current processor shown in FIG. 6, which will be described below.

FIG. 4 is a diagram illustrating an example of a current signal processing unit among the signal conditioning units of the arc generation warning system of FIG. 1. As shown in FIG. 4, output currents CT_IN1, CT_IN2, and CT_IN3 are respectively inputted from the current sensor circuit of FIG. 3. After rectifying through the high pass filter (HPF), amplifying and outputting only a signal of a predetermined current value or more through the comparator.

In this case, some of the circuits indicated by the dotted lines of FIG. 4 remove portions of the fundamental frequency component (60 Hz) of the current signal input through the current sensor circuit of FIG. 3. The signals IntR, IntS, and IntT respectively output from the current signal processor are applied to the DSP of FIG. 7 described below.

FIG. 5 is a diagram illustrating a power supply voltage frequency signal detection unit of the signal conditioning unit of the arc generation warning system of FIG. 1, and outputs the voltages V1, V2, and V3 from the power supply voltage frequency signal detector of FIG. And a signal processing circuit for outputting the frequency component of each voltage. When the voltage across the output has a positive value, the output goes HIGH and, conversely, if the voltage on the output has a positive value, the output goes LOW. The output signals IntFR, IntFS, and IntFT of the power voltage frequency signal detector are applied to the DSP of FIG. 7 described below.

FIG. 6 is a diagram illustrating an embodiment of a load current processing unit of a signal conditioning unit of the arc generation alarm system of FIG. 1. As shown in FIG. 6, output currents CT_IN1, CT_IN2, and CT_IN3 are respectively input from the current sensor circuit of FIG. 3. After rectifying through the high pass filter (HPF), amplifying and smoothing, only signals of a predetermined current value or more are output through the comparator. The signals CUR_IN_R, CUR_IN_S, and CUR_IN_T respectively output from the load current processing unit are applied to the A / D input ports of the DSP of FIG. 7 to be described below, and the current magnitude of the load from the load current to which the DSP is input. Transfer to an external surveillance system.

FIG. 7 is a diagram illustrating an embodiment of a central processing unit and an alarm output unit of the arc generation warning system of FIG. 1. As illustrated, the DSP chip outputs signals IntR, IntS, and IntT input from the current signal processor of FIG. 4. And output signals IntFR, IntFS, and IntFT input from the power voltage frequency signal detector of FIG. 5 and output signals CUR_IN_R, CUR_IN_S, and CUR_IN_T respectively input from the load current processor of FIG. 6. The DSP chip is the central processing unit 30 of FIG. 1, and counts an arc component of an input current per cycle and calculates a pulse width thereof. The DSP chip applies a control signal to the alarm output unit 40 to generate an alarm when the number of input pulses exceeds a set value or the width of the pulse is greater than or equal to a predetermined value. At this time, the set value of the number of pulses and the constant value of the pulse width is set in advance to the set value verified through the test of the authorized institution and apply the same in all sites.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited by the described embodiments, but should be determined by the scope of the appended claims and equivalents thereof.

1 is a block diagram of an arc generation alarm system according to a preferred embodiment of the present invention;

Figure 2 is an embodiment of the voltage sensor of the sensor unit of the arc generation alarm system of Figure 1,

Figure 3 is an embodiment of the current sensor of the sensor unit of the arc generation alarm system of Figure 1,

4 is a diagram illustrating an embodiment of a current signal processing unit among signal conditioning units of the arc generation warning system of FIG. 1;

5 is a diagram illustrating an exemplary embodiment of a power supply voltage frequency signal detection unit of a signal conditioning unit of the arc generation alarm system of FIG. 1;

FIG. 6 is a diagram illustrating one embodiment of a load current processing unit among signal conditioning units of the arc generation alarm system of FIG. 1;

7 is a diagram illustrating one embodiment of a central processing unit and an alarm output unit of the arc generation alarm system of FIG.

Claims (7)

In the arc detection method for detecting the arc in the power distribution system to determine whether it is a normal arc or a faulted arc and to generate an alarm and a trip signal, The electric signal in the power distribution system is separated into a current signal and a voltage signal, and the voltage signal of the same phase as the current signal is converted into a frequency component, and the remaining arc components except the basic frequency component of the current signal are extracted. An arc detection method in a power distribution system, characterized in that the arc generation is recognized by the number of pulses input and the width of the pulse per cycle of the extracted arc component. The method of claim 1, wherein the number of pulses input and the width of the pulses per one period of the extracted arc component, A method for detecting arcs in a power distribution system, characterized by a sudden increase in the number of pulse inputs in the previous several sections and the occurrence of abnormal arcs when the pulse width is random. In the arc generation alarm system using the arc detection method for detecting the arc in the power distribution system to determine whether it is a normal arc or a faulted arc and to generate an alarm and a trip signal, A sensor unit for arc detection; A signal conditioning unit for separating an arc component by receiving a current signal output from the sensor unit; A central processing unit for calculating the number and width of pulses input per cycle of the arc input from the signal conditioning unit and distinguishing between normal arcs and abnormal arcs based on this; And And an alarm output unit configured to generate a trip signal and an arc generation alarm under the control of the central processing unit. The arc generation warning system using the arc detection method in the power distribution system, comprising: a. The method of claim 3, wherein the sensor unit, Arc generation alarm system using the arc detection method in the power distribution system, characterized in that consisting of a voltage sensor circuit and a current sensor circuit for separating and outputting the voltage and current in the power distribution system, respectively. The method of claim 3, wherein the signal conditioning unit, It consists of a power supply voltage frequency signal detector for converting the voltage signal input from the sensor unit into a frequency component and outputting it, and a current signal processing unit for rectifying and amplifying the current signal input from the sensor unit and outputting only a current signal of a predetermined current value or more. Arc generation alarm system using the arc detection method in the power distribution system characterized in that. The method of claim 5, wherein the signal conditioning unit, And a load current processing unit for rectifying, amplifying and smoothing the current signal inputted from the sensor unit, and outputting the load current for calculation of load current. The method of claim 3, wherein the central processing unit, The number and width of the input pulses per cycle of the arc input from the signal conditioning unit is increased more rapidly than the number of pulse inputs of the previous several intervals, and if the pulse width is random, it is determined that abnormal arc has occurred Arc generation alarm system using arc detection method in the system.

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