CN116706836A - Implementation method, device, medium and equipment for releasing inrush current blocking of transformer - Google Patents
Implementation method, device, medium and equipment for releasing inrush current blocking of transformer Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/04—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for transformers
- H02H7/045—Differential protection of transformers
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Abstract
The invention discloses a realization method, a device, a medium and equipment for releasing inrush current blocking of a transformer. The method comprises the following steps: calculating differential current sampling values of the transformer corresponding to sampling points spaced by a first preset time period in real time according to the current sampling values of each side of the transformer; under the condition that the differential current sampling value meets a preset starting criterion, determining the starting moment of the starting criterion; determining an unlocking current generation interval and a floating threshold interval of each current calculation time in a power frequency period according to the starting time and the differential current sampling value at the starting time; determining unlocking current and floating threshold current at each current calculation moment according to the generated unlocking current interval and the generated differential current sampling value of the floating threshold interval; and under the condition that the unlocking current and the floating threshold current at any current calculation moment meet the preset unlocking inrush current locking criterion, determining that the transformer unlocks the inrush current.
Description
Technical Field
The invention relates to the technical field of power transformers, in particular to a realization method, a device, a medium and equipment for releasing inrush current blocking of a transformer.
Background
The power transformer is an important device of a power plant and a transformer substation, and the safe operation of the power transformer is directly related to the continuous stable operation of the whole power system. The exciting current of the transformer is a special electromagnetic phenomenon, and the maximum exciting current can reach 4-8 times of the normal running current, and is a main source for causing the misoperation of the differential protection of the transformer, so the differential protection of the transformer usually needs to be operated by an exciting current locking criterion.
When a developing fault occurs to the transformer, the differential protection of the transformer is easily locked by the excitation surge locking criterion in the change process of fault development, so that the differential protection of the transformer cannot cut off the fault in time, thereby affecting the operation life of the transformer, causing serious damage to the transformer and even serious consequences of the burnout of the transformer.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a realization method, a device, a medium and equipment for releasing inrush current blocking of a transformer.
According to one aspect of the invention, there is provided a method for implementing inrush current blocking release of a transformer, including:
Calculating differential current sampling values of the transformer corresponding to sampling points spaced by a first preset time period in real time according to the current sampling values of each side of the transformer;
under the condition that the differential current sampling value meets a preset starting criterion, determining the starting moment of the starting criterion;
determining an unlocking current generation interval and a floating threshold interval of each current calculation time in a power frequency period according to the starting time and the differential current sampling value at the starting time;
determining unlocking current and floating threshold current at each current calculation moment according to the generated unlocking current interval and the generated differential current sampling value of the floating threshold interval;
and under the condition that the unlocking current and the floating threshold current at any current calculation moment meet the preset unlocking inrush current locking criterion, determining that the transformer unlocks the inrush current.
Optionally, the start criteria are as follows:
the calculation formula of the differential current sampling value is as follows:
wherein ,is a transformer->Phase-difference current sample value>A. B, C is three-phase of transformer, +.>For the current sampling value of the ith side of the transformer after balance coefficient conversion and phase correction, I e Is the rated current of the transformer.
Optionally, determining an unlock current interval and a floating threshold interval generated at each current calculation time in the power frequency period according to the starting time and the differential current sampling value at the starting time, including:
determining the generated unlocking current interval time length of each current calculation time according to the starting time, the differential current sampling value of the time and a preset generated unlocking current interval time length criterion;
and determining a generated floating threshold interval and a generated unlocking current interval of each current calculation time according to the starting time and the time length of the generated unlocking current interval.
Optionally, the unlocking current interval time length criterion is generated as follows:
wherein ,t0 In order to start up the moment of time,for the start-up time differential current sampling value, < >>A. B, C is three-phase of transformer, +.>At t 0 Differential current sampling value at +2Δt; Δt is the basic time unit of the criterion, and
determining the generated unlocking current interval time length of each current calculation time according to the starting time, the differential current sampling value at the time and a preset generated unlocking current interval time length criterion, wherein the method comprises the following steps of:
determining the time length T of the generated unlocking current interval under the condition that the differential current sampling value at the starting time and the differential current sampling value at the starting time meet the time length criterion of the generated unlocking current interval Σ ＝3Δt；
Determining the time length T of the generated unlocking current interval under the condition that the differential current sampling value at the starting time and the time does not meet the time length criterion of the generated unlocking current interval Σ ＝2Δt。
Optionally, determining the unlock current and the floating threshold current at each current computing time according to the differential current sampling values of the unlock current interval and the floating threshold interval comprises:
according to the maximum value of the absolute value of the differential current sampling value in the generated unlocking current interval at each current calculation time, determining the maximum unlocking current, wherein the calculation formula is as follows:
wherein ,for maximum unlocking current, +.>A. B, C is three-phase of transformer, +.>For differential current sampling, [ T-T ] Σ ,t]Generating an unlocking current interval, wherein T is the current calculation time, and T Σ Generating an unlocking current interval time length;
according to the maximum value of the absolute value of the differential current sampling value in the generated floating threshold interval at each current calculation moment, the maximum floating threshold current is determined, and the calculation formula is as follows:
wherein ,for maximum floating threshold current +.>A. B, C is three-phase of transformer, +.>For differential current sample value, [ t ] 0 ,t-T Σ ) To generate a floating threshold interval, t 0 For starting time, T is the current calculation time, T Σ Generating an unlocking current interval time length;
determining the floating threshold current at each current calculation time according to the differential current sampling value corresponding to the maximum unlocking current at each current calculation time and the differential current sampling value corresponding to the maximum floating threshold current;
and determining the unlocking current of each current computing moment according to the differential current sampling value of each sampling point in the generated unlocking current interval of each current computing moment and the maximum unlocking current.
Optionally, determining the floating threshold current at each current computing time according to the differential current sampling value corresponding to the maximum unlocking current at each current computing time and the differential current sampling value corresponding to the maximum floating threshold current includes:
under the condition that the differential current sampling value corresponding to the maximum unlocking current and the differential current sampling value corresponding to the maximum floating threshold current at each current calculation moment meet the extremum criterion, the floating threshold current at the current calculation moment is the maximum floating threshold current, wherein the extremum criterion is as follows:
wherein ,differential current sampling value corresponding to maximum unlocking current, < >>A. B, C is three-phase of transformer, +.>The differential current sampling value corresponding to the maximum floating threshold current is obtained;
Under the condition that the differential current sampling value corresponding to the maximum unlocking current and the differential current sampling value corresponding to the maximum floating threshold current at each current calculation time do not meet the extremum criterion, the floating threshold current at the current calculation time is:
wherein ,for floating threshold current, ">For maximum floating threshold current +.>A. B, C is three-phase of transformer, +.>Is the maximum unlocking current.
Optionally, the excitation surge current blocking cancellation criteria are:
wherein ,for unlocking the current +.>A. B, C is a three-phase transformer and,for floating threshold current, ">To generate an integration result of differential current sampling values in the unlock current interval, n is the number of sampling points in the unlock current interval.
According to another aspect of the present invention, there is provided an implementation apparatus for releasing inrush current blocking of a transformer, including:
the calculation module is used for calculating differential current sampling values of the transformer corresponding to sampling points spaced by a first preset time period in real time according to the current sampling values of each side of the transformer;
the first determining module is used for determining the starting moment of the starting criterion under the condition that the differential current sampling value meets the preset starting criterion;
the second determining module is used for determining an unlocking current interval and a floating threshold interval generated at each current calculation time in the power frequency period according to the starting time and the differential current sampling value at the starting time;
The third determining module is used for determining unlocking current and floating threshold current at each current computing moment according to the generated unlocking current interval and the generated differential current sampling value of the floating threshold interval;
and the fourth determining module is used for determining that the transformer releases the excitation surge current locking under the condition that the unlocking current and the floating threshold current at any current calculation moment meet the preset excitation surge current releasing locking criterion.
According to a further aspect of the present application there is provided a computer readable storage medium storing a computer program for performing the method according to any one of the above aspects of the present application.
According to still another aspect of the present application, there is provided an electronic device including: a processor; a memory for storing the processor-executable instructions; the processor is configured to read the executable instructions from the memory and execute the instructions to implement the method according to any of the above aspects of the present application.
Therefore, the realization method for releasing the inrush current blocking of the transformer provided by the application determines the starting moment of the starting criterion by calculating the differential current sampling value of the transformer corresponding to the sampling point of the first preset time interval and the starting criterion. And then circularly calculating to generate an unlocking current interval and a floating threshold interval in a period, and determining the unlocking current and the floating threshold current at each current calculation moment. And under the condition that the unlocking current and the floating threshold current at any current calculation moment meet the preset unlocking inrush current locking criterion, determining that the transformer unlocks the inrush current. And then the small turns of the transformer are developed into a large turn-to-turn short circuit after the surge is blocked, so that the action speed of fault protection of the transformer is accelerated, and the operation life of the transformer is prolonged.
Drawings
Exemplary embodiments of the present invention may be more completely understood in consideration of the following drawings:
FIG. 1 is a flow chart of a method for implementing a transformer to release inrush current blocking according to an exemplary embodiment of the present invention;
FIG. 2 is another flow chart of a method for implementing a transformer to unlock inrush current according to an exemplary embodiment of the present invention;
FIG. 3 is a schematic diagram of a time axis for unlocking a transformer inrush current locking criterion provided by an exemplary embodiment of the present invention;
FIG. 4 is a schematic diagram of determining to generate an unlock current interval and generating a floating threshold interval provided by an exemplary embodiment of the present invention;
FIG. 5 is a schematic diagram of the results of transformer turn-to-turn developing fault actions provided by an exemplary embodiment of the present invention;
FIG. 6 is a schematic diagram of a result of an inrush current occurring in a transformer inter-turn space charge according to an exemplary embodiment of the present invention;
FIG. 7 is a schematic diagram of the results of transformer inter-turn occurrences and stress current actions provided by an exemplary embodiment of the present invention;
FIG. 8 is a schematic diagram of a result of a transformer inter-turn restorative inrush current action provided by an exemplary embodiment of the present invention;
fig. 9 is a schematic structural diagram of an implementation device for releasing inrush current blocking of a transformer according to an exemplary embodiment of the present invention;
Fig. 10 is a structure of an electronic device provided in an exemplary embodiment of the present invention.
Detailed Description
Hereinafter, exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings. It should be apparent that the described embodiments are only some embodiments of the present invention and not all embodiments of the present invention, and it should be understood that the present invention is not limited by the example embodiments described herein.
It should be noted that: the relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless it is specifically stated otherwise.
It will be appreciated by those of skill in the art that the terms "first," "second," etc. in embodiments of the present invention are used merely to distinguish between different steps, devices or modules, etc., and do not represent any particular technical meaning nor necessarily logical order between them.
It should also be understood that in embodiments of the present invention, "plurality" may refer to two or more, and "at least one" may refer to one, two or more.
It should also be appreciated that any component, data, or structure referred to in an embodiment of the invention may be generally understood as one or more without explicit limitation or the contrary in the context.
In addition, the term "and/or" in the present invention is merely an association relationship describing the association object, and indicates that three relationships may exist, for example, a and/or B may indicate: a exists alone, A and B exist together, and B exists alone. In the present invention, the character "/" generally indicates that the front and rear related objects are an or relationship.
It should also be understood that the description of the embodiments of the present invention emphasizes the differences between the embodiments, and that the same or similar features may be referred to each other, and for brevity, will not be described in detail.
Meanwhile, it should be understood that the sizes of the respective parts shown in the drawings are not drawn in actual scale for convenience of description.
The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods, and apparatus should be considered part of the specification.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.
Embodiments of the invention are operational with numerous other general purpose or special purpose computing system environments or configurations with electronic devices, such as terminal devices, computer systems, servers, etc. Examples of well known terminal devices, computing systems, environments, and/or configurations that may be suitable for use with the terminal device, computer system, server, or other electronic device include, but are not limited to: personal computer systems, server computer systems, thin clients, thick clients, hand-held or laptop devices, microprocessor-based systems, set-top boxes, programmable consumer electronics, network personal computers, small computer systems, mainframe computer systems, and distributed cloud computing technology environments that include any of the foregoing, and the like.
Electronic devices such as terminal devices, computer systems, servers, etc. may be described in the general context of computer system-executable instructions, such as program modules, being executed by a computer system. Generally, program modules may include routines, programs, objects, components, logic, data structures, etc., that perform particular tasks or implement particular abstract data types. The computer system/server may be implemented in a distributed cloud computing environment in which tasks are performed by remote processing devices that are linked through a communications network. In a distributed cloud computing environment, program modules may be located in both local and remote computing system storage media including memory storage devices.
Exemplary method
Fig. 1 is a flow chart of a method for implementing the current surge blocking release of a transformer according to an exemplary embodiment of the present invention. The embodiment can be applied to an electronic device, as shown in fig. 1, the implementation method 100 for releasing the inrush current blocking of a transformer includes the following steps:
step 101, referring to fig. 1 and 2, differential current sampling values of the transformer corresponding to sampling points spaced by a first predetermined period are calculated in real time according to current sampling values of each side of the transformer.
Step 102, referring to fig. 1 and 2, in the case that the differential current sampling value meets the preset starting criterion, determining the starting moment of the starting criterion.
Optionally, the start criteria are as follows:
the calculation formula of the differential current sampling value is as follows:
wherein ,is a transformer->Phase-difference current sample value>A. B, C is three-phase of transformer, +.>For the current sampling value of the ith side of the transformer after balance coefficient conversion and phase correction, I e Is the rated current of the transformer.
Specifically, the moment when the start criterion satisfies the condition is the start criterion start moment t 0 。
Step 103, referring to fig. 1 and 2, determining an unlock current interval generated at each current calculation time and a floating threshold interval generated in the power frequency period according to the start time and the differential current sampling value at the start time.
Optionally, determining an unlock current interval and a floating threshold interval generated at each current calculation time in the power frequency period according to the starting time and the differential current sampling value at the starting time, including:
determining the generated unlocking current interval time length of each current calculation time according to the starting time, the differential current sampling value of the time and a preset generated unlocking current interval time length criterion;
and determining a generated floating threshold interval and a generated unlocking current interval of each current calculation time according to the starting time and the time length of the generated unlocking current interval.
Optionally, the unlocking current interval time length criterion is generated as follows:
wherein ,t0 In order to start up the moment of time,for the start-up time differential current sampling value, < >>A. B, C is the three phases of a transformer; />At t 0 Differential current sampling value at +2Δt; Δt is the basic time unit of the criterion, and
determining the generated unlocking current interval time length of each current calculation time according to the starting time, the differential current sampling value at the time and a preset generated unlocking current interval time length criterion, wherein the method comprises the following steps of:
determining the time length T of the generated unlocking current interval under the condition that the differential current sampling value at the starting time and the differential current sampling value at the starting time meet the time length criterion of the generated unlocking current interval Σ ＝3Δt；
Determining the time length T of the generated unlocking current interval under the condition that the differential current sampling value at the starting time and the time does not meet the time length criterion of the generated unlocking current interval Σ ＝2Δt。
Specifically, referring to FIG. 3, the current calculation time is T, and the generated unlock current interval is [ T-T ] Σ ,t]The method comprises the steps of carrying out a first treatment on the surface of the The starting time of the starting criterion is t 0 Generating a floating threshold interval as [ t ] 0 ,t-T Σ )。
Calculating and generating a floating threshold interval and an unlocking current interval in one power frequency period, namely, from t 0 Starting calculation at +5Δt time to t 0 The +5Δt+t one calculation cycle ends.
Referring to FIG. 4, at T Σ ＝3Δt，t＝t 0 When +5Δt, generating an unlock current interval of [ t ] 0 +2Δt,t 0 +5Δt]Generating a floating threshold interval as [ t ] 0 ,t 0 +2Δt), where Δt may be, but is not limited to, 2.5ms.
At T Σ ＝2Δt，t＝t 0 When +5Δt, generating an unlock current interval of [ t ] 0 +3Δt,t 0 +5Δt]Generating a floating threshold interval as [ t ] 0 ,t 0 +3Δt)。
Step 104, referring to fig. 1 and 2, determining the unlock current and the floating threshold current at each present calculation time according to the differential current sampling values of the unlock current interval and the floating threshold interval.
Optionally, determining the unlock current and the floating threshold current at each current computing time according to the differential current sampling values of the unlock current interval and the floating threshold interval comprises:
According to the maximum value of the absolute value of the differential current sampling value in the generated unlocking current interval at each current calculation time, determining the maximum unlocking current, wherein the calculation formula is as follows:
wherein ,for maximum unlocking current, +.>A. B, C is three-phase of transformer, +.>For differential current sampling, [ T-T ] Σ ,t]Generating an unlocking current interval, wherein T is the current calculation time, and T Σ Generating an unlocking current interval time length;
according to the maximum value of the absolute value of the differential current sampling value in the generated floating threshold interval at each current calculation moment, the maximum floating threshold current is determined, and the calculation formula is as follows:
wherein ,for maximum floating threshold current +.>A. B, C is three-phase of transformer, +.>For differential current sample value, [ t ] 0 ,t-T Σ ) To generate a floating threshold interval, t 0 For starting time, T is the current calculation time, T Σ Generating an unlocking current interval time length;
determining the floating threshold current at each current calculation time according to the differential current sampling value corresponding to the maximum unlocking current at each current calculation time and the differential current sampling value corresponding to the maximum floating threshold current;
and determining the unlocking current of each current computing moment according to the differential current sampling value of each sampling point in the generated unlocking current interval of each current computing moment and the maximum unlocking current.
Optionally, determining the floating threshold current at each current computing time according to the differential current sampling value corresponding to the maximum unlocking current at each current computing time and the differential current sampling value corresponding to the maximum floating threshold current includes:
under the condition that the differential current sampling value corresponding to the maximum unlocking current and the differential current sampling value corresponding to the maximum floating threshold current at each current calculation moment meet the extremum criterion, the floating threshold current at the current calculation moment is the maximum floating threshold current, wherein the extremum criterion is as follows:
wherein ,differential current sampling value corresponding to maximum unlocking current, < >>A. B, C is the three phases of a transformer; />The differential current sampling value corresponding to the maximum floating threshold current is obtained;
under the condition that the differential current sampling value corresponding to the maximum unlocking current and the differential current sampling value corresponding to the maximum floating threshold current at each current calculation time do not meet the extremum criterion, the floating threshold current at the current calculation time is:
wherein ,for floating threshold current, ">For maximum floating threshold current +.>A. B, C is three-phase of transformer, +.>Is the maximum unlocking current.
Step 105, referring to fig. 1 and 2, determining that the transformer is locked by the excitation surge current when the unlock current and the floating threshold current at any one of the current calculation times satisfy a preset excitation surge current locking release criterion.
Optionally, the excitation surge current blocking cancellation criteria are:
wherein ,for unlocking the current +.>A. B, C is a three-phase transformer and,for floating threshold current, ">To generate an integration result of differential current sampling values in the unlock current interval, n is the number of sampling points in the unlock current interval.
Specifically, at t 0 And +5Deltat+T is the periodic cycle calculation, and under the condition that the unlocking current and the floating threshold current at any current calculation moment meet the preset unlocking inrush current locking criterion, the unlocking inrush current locking of the transformer is determined.
Further, referring to fig. 5, an example of a developing fault applied to a transformer is shown
The transformer turn-to-turn developing fault scene is that a transformer is developed from a small turn-to-turn fault to a serious turn-to-turn fault, a fault phase is a B phase, the transformer is always in a state of magnetizing inrush current locking differential protection from the fault, the fault is developed to the serious turn-to-turn fault at 28ms, a condition is met by a condition for releasing the magnetizing inrush current locking criterion of the transformer at 32.5ms, and the transformer inrush current locking is released.
Further, referring to fig. 6, an example in which excitation inrush current occurs in the transformer air charge is shown.
When the transformer is in no-load condition, the transformer is charged in a closing mode, exciting current is generated by the transformer, and in the period of the exciting current, the exciting current locking criterion of the transformer is not met all the time when the developing fault of the transformer releases the exciting current, and the transformer is in a state of the exciting current locking differential protection and does not generate misoperation.
Further, referring to fig. 7, an example of transformer occurrence and stress current is shown.
When the adjacent transformers are charged in a no-load closing manner, the transformers can generate and respond to the current, and in the period of generating and responding to the current, the excitation current locking criterion for releasing the development fault of the transformers is always not met, and the transformers are in the state of locking differential protection by the excitation current, so that misoperation does not occur.
Further, referring to FIG. 8, an example of a restorative inrush current occurring for a transformer is shown
When the same bus transformer fails, in the process of removing the bus voltage recovery, the recovery inrush current of the no-load running transformer can occur, taking the phase A with the most serious inrush current as an example, and during the recovery inrush current, the condition is not met all the time when the transformer development fault releases the excitation inrush current locking criterion, and the transformer is in the state of excitation inrush current locking differential protection, so that misoperation does not occur.
Therefore, the realization method for releasing the inrush current blocking of the transformer provided by the application determines the starting moment of the starting criterion by calculating the differential current sampling value of the transformer corresponding to the sampling point of the first preset time interval and the starting criterion. And then circularly calculating to generate an unlocking current interval and a floating threshold interval in a period, and determining the unlocking current and the floating threshold current at each current calculation moment. And under the condition that the unlocking current and the floating threshold current at any current calculation moment meet the preset unlocking inrush current locking criterion, determining that the transformer unlocks the inrush current. And then quickly cutting off the small turn-to-turn of the transformer after being blocked by the inrush current to develop into a large turn-to-turn short circuit, thereby accelerating the action speed of the fault protection of the transformer.
Exemplary apparatus
Fig. 9 is a schematic structural diagram of an implementation device for releasing inrush current blocking of a transformer according to an exemplary embodiment of the present invention. As shown in fig. 9, the apparatus 900 includes:
a calculating module 910, configured to calculate, in real time, differential current sampling values of the transformer corresponding to sampling points spaced by a first predetermined period according to current sampling values of each side of the transformer;
a first determining module 920, configured to determine a starting time of the starting criterion when the differential current sampling value meets a preset starting criterion;
a second determining module 930, configured to determine, according to the start time and the differential current sampling value at the start time, an unlock current interval generated at each current calculation time in the power frequency period and a floating threshold interval generated;
a third determining module 940, configured to determine an unlock current and a floating threshold current at each current computing time according to the generated unlock current interval and the generated differential current sampling value of the floating threshold interval;
and a fourth determining module 950, configured to determine that the transformer releases the inrush current blocking when the unlock current and the floating threshold current at any one of the current computing moments meet a preset inrush current release blocking criterion.
Optionally, the start criteria are as follows:
the calculation formula of the differential current sampling value is as follows:
wherein ,is a transformer->Phase-difference current sample value>A. B, C is three-phase of transformer, +.>For the current sampling value of the ith side of the transformer after balance coefficient conversion and phase correction, I e Is the rated current of the transformer.
Optionally, the second determining module 930 includes:
the first determining submodule is used for determining the time length of the generated unlocking current interval at each current computing moment according to the starting moment, the differential current sampling value at the moment and the preset time length criterion of the generated unlocking current interval;
and the second determining submodule is used for determining a generated floating threshold interval and a generated unlocking current interval at each current calculation moment according to the starting moment and the time length of the generated unlocking current interval.
Optionally, the unlocking current interval time length criterion is generated as follows:
wherein ,t0 In order to start up the moment of time,for the start-up time differential current sampling value, < >>A. B, C is the three phases of a transformer; />At t 0 Differential current sampling value at +2Δt; Δt is the basic time unit of the criterion, and
a first determination submodule comprising:
a first determining unit for determining the generated unlocking current interval time length T when the differential current sampling value at the starting time meets the generated unlocking current interval time length criterion Σ ＝3Δt；
A second determining unit for determining the generated unlocking current interval time length T when the differential current sampling value at the starting time does not meet the generated unlocking current interval time length criterion Σ ＝2Δt。
Optionally, the third determining module 940 includes:
the third determining submodule is used for determining the maximum unlocking current according to the maximum value of the absolute value of the differential current sampling value in the unlocking current generating interval at each current computing moment, and the computing formula is as follows:
wherein ,for maximum unlocking current, +.>A. B, C is three-phase of transformer, +.>For differential current sampling, [ T-T ] Σ ,t]Generating an unlocking current interval, wherein T is the current calculation time, and T Σ Generating an unlock current interval is longA degree;
the fourth determining submodule is used for determining the maximum floating threshold current according to the maximum value of the absolute value of the differential current sampling value in the generated floating threshold interval at each current calculating moment, and the calculating formula is as follows:
wherein ,for maximum floating threshold current +.>A. B, C is three-phase of transformer, +.>For differential current sample value, [ t ] 0 ,t-T Σ ) To generate a floating threshold interval, t 0 For starting time, T is the current calculation time, T Σ Generating an unlocking current interval time length;
A fifth determining submodule, configured to determine a floating threshold current at each current computation time according to a differential current sampling value corresponding to a maximum unlock current at each current computation time and a differential current sampling value corresponding to a maximum floating threshold current;
and the sixth determining submodule is used for determining the unlocking current of each current computing moment according to the differential current sampling value of each sampling point in the unlocking current generating interval of each current computing moment and the maximum unlocking current.
Optionally, the fifth determining submodule includes:
the third determining unit is configured to, when the differential current sampling value corresponding to the maximum unlock current and the differential current sampling value corresponding to the maximum floating threshold current at each current calculation time satisfy an extremum criterion, determine that the floating threshold current at the current calculation time is the maximum floating threshold current, where the extremum criterion is as follows:
wherein ,differential current sampling value corresponding to maximum unlocking current, < >>A. B, C is the three phases of a transformer; />The differential current sampling value corresponding to the maximum floating threshold current is obtained;
the fourth determining unit is configured to, when the differential current sampling value corresponding to the maximum unlock current and the differential current sampling value corresponding to the maximum floating threshold current at each current calculation time do not satisfy the extremum criterion, determine that the floating threshold current at the current calculation time is:
wherein ,for floating threshold current, ">For maximum floating threshold current +.>A. B, C is three-phase of transformer, +.>Is the maximum unlocking current.
Optionally, the excitation surge current blocking cancellation criteria are:
wherein ,for unlocking the current +.>A. B, C is three of transformers
The phase of the liquid phase is selected,for floating threshold current, ">To generate an integration result of differential current sampling values in the unlock current interval, n is the number of sampling points in the unlock current interval.
Exemplary electronic device
Fig. 10 is a structure of an electronic device provided in an exemplary embodiment of the present invention. As shown in fig. 10, the electronic device 100 includes one or more processors 101 and memory 102.
The processor 101 may be a Central Processing Unit (CPU) or other form of processing unit having data processing and/or instruction execution capabilities and may control other components in the electronic device to perform desired functions.
Memory 102 may include one or more computer program products that may include various forms of computer-readable storage media, such as volatile memory and/or non-volatile memory. The volatile memory may include, for example, random Access Memory (RAM) and/or cache memory (cache), and the like. The non-volatile memory may include, for example, read Only Memory (ROM), hard disk, flash memory, and the like. One or more computer program instructions may be stored on the computer readable storage medium that can be executed by the processor 101 to implement the methods of the software programs of the various embodiments of the present invention described above and/or other desired functions. In one example, the electronic device may further include: an input device 103 and an output device 104, which are interconnected by a bus system and/or other forms of connection mechanisms (not shown).
In addition, the input device 103 may also include, for example, a keyboard, a mouse, and the like.
The output device 104 can output various information to the outside. The output device 104 may include, for example, a display, speakers, a printer, and a communication network and remote output apparatus connected thereto, etc.
Of course, only some of the components of the electronic device relevant to the present invention are shown in fig. 10 for simplicity, components such as buses, input/output interfaces, etc. being omitted. In addition, the electronic device may include any other suitable components depending on the particular application.
Exemplary computer program product and computer readable storage Medium
In addition to the methods and apparatus described above, embodiments of the invention may also be a computer program product comprising computer program instructions which, when executed by a processor, cause the processor to perform steps in a method according to various embodiments of the invention described in the "exemplary methods" section of this specification.
The computer program product may write program code for performing operations of embodiments of the present invention in any combination of one or more programming languages, including an object oriented programming language such as Java, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computing device, partly on the user's device, as a stand-alone software package, partly on the user's computing device, partly on a remote computing device, or entirely on the remote computing device or server.
Furthermore, embodiments of the invention may also be a computer-readable storage medium, having stored thereon computer program instructions, which when executed by a processor, cause the processor to perform steps in a method according to various embodiments of the invention described in the "exemplary method" section of the description above.
The computer readable storage medium may employ any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. The readable storage medium can include, for example, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, or device, or a combination of any of the foregoing. More specific examples (a non-exhaustive list) of the readable storage medium would include the following: an electrical connection having one or more wires, a portable disk, a hard disk, random Access Memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.
The basic principles of the present invention have been described above in connection with specific embodiments, however, it should be noted that the advantages, benefits, effects, etc. mentioned in the present invention are merely examples and not intended to be limiting, and these advantages, benefits, effects, etc. are not to be considered as essential to the various embodiments of the present invention. Furthermore, the specific details disclosed herein are for purposes of illustration and understanding only, and are not intended to be limiting, as the invention is not necessarily limited to practice with the above described specific details.
In this specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different manner from other embodiments, so that the same or similar parts between the embodiments are mutually referred to. For system embodiments, the description is relatively simple as it essentially corresponds to method embodiments, and reference should be made to the description of method embodiments for relevant points.
The block diagrams of the devices, systems, apparatuses, systems according to the present invention are merely illustrative examples and are not intended to require or imply that the connections, arrangements, configurations must be made in the manner shown in the block diagrams. As will be appreciated by one of skill in the art, the devices, systems, apparatuses, systems may be connected, arranged, configured in any manner. Words such as "including," "comprising," "having," and the like are words of openness and mean "including but not limited to," and are used interchangeably therewith. The terms "or" and "as used herein refer to and are used interchangeably with the term" and/or "unless the context clearly indicates otherwise. The term "such as" as used herein refers to, and is used interchangeably with, the phrase "such as, but not limited to.
The method and system of the present invention may be implemented in a number of ways. For example, the methods and systems of the present invention may be implemented by software, hardware, firmware, or any combination of software, hardware, firmware. The above-described sequence of steps for the method is for illustration only, and the steps of the method of the present invention are not limited to the sequence specifically described above unless specifically stated otherwise. Furthermore, in some embodiments, the present invention may also be embodied as programs recorded in a recording medium, the programs including machine-readable instructions for implementing the methods according to the present invention. Thus, the present invention also covers a recording medium storing a program for executing the method according to the present invention.
It is also noted that in the systems, devices and methods of the present invention, components or steps may be disassembled and/or assembled. Such decomposition and/or recombination should be considered as equivalent aspects of the present invention. The previous description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects without departing from the scope of the invention. Thus, the present invention is not intended to be limited to the aspects shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
The foregoing description has been presented for purposes of illustration and description. Furthermore, this description is not intended to limit embodiments of the invention to the form disclosed herein. Although a number of example aspects and embodiments have been discussed above, a person of ordinary skill in the art will recognize certain variations, modifications, alterations, additions, and subcombinations thereof.
Claims (10)
1. The realization method for releasing the inrush current blocking of the transformer is characterized by comprising the following steps of:
calculating differential current sampling values of the transformer corresponding to sampling points spaced by a first preset time period in real time according to the current sampling values of each side of the transformer;
determining the starting moment of the starting criterion under the condition that the differential current sampling value meets the preset starting criterion;
determining an unlocking current generation interval and a floating threshold interval of each current calculation time in a power frequency period according to the starting time and the differential current sampling value at the starting time;
determining unlocking current and floating threshold current at each current computing moment according to the generated unlocking current interval and the differential current sampling value of the generated floating threshold interval;
and under the condition that the unlocking current and the floating threshold current at any one current calculation moment meet a preset unlocking inrush current locking criterion, determining that the transformer unlocks the inrush current.
2. The method according to claim 1, characterized in that the start-up criterion is as follows:
the calculation formula of the differential current sampling value is as follows:
wherein ,for differential current sampling, ">A. B, C is a transformer three-phase->For the current sampling value of the ith side of the transformer after balance coefficient conversion and phase correction, I e Is the rated current of the transformer.
3. The method of claim 1, wherein determining a generated unlock current interval and a generated float threshold interval for each present calculation time in a power frequency cycle based on the start time and the differential current sample value at that time comprises:
determining the generated unlocking current interval time length of each current calculation time according to the starting time, the differential current sampling value at the time and a preset generated unlocking current interval time length criterion;
and determining the generated floating threshold interval and the generated unlocking current interval of each current calculation time according to the starting time and the time length of the generated unlocking current interval.
4. A method according to claim 3, wherein the generated unlock current interval time length criterion is as follows:
wherein ,t0 In order to start up the moment of time,for the start-up time differential current sampling value, < >>A. B, C is the three phases of a transformer; />At t 0 Differential current sampling value at +2Δt; Δt is the basic time unit of the criterion, and
determining the generated unlocking current interval time length of each current computing moment according to the starting moment, the differential current sampling value at the moment and a preset generated unlocking current interval time length criterion, wherein the method comprises the following steps of:
determining the generated unlocking current interval time length T under the condition that the starting time and the differential current sampling value at the starting time meet the generated unlocking current interval time length criterion Σ ＝3Δt；
Determining the generated unlocking current interval time length T under the condition that the starting time and the differential current sampling value at the time do not meet the generated unlocking current interval time length criterion Σ ＝2Δt。
5. The method of claim 1, wherein determining the unlock current and the floating threshold current for each present computing time based on the differential current sample values for the generated unlock current interval and the generated floating threshold interval comprises:
determining the maximum unlocking current according to the maximum value of the absolute value of the differential current sampling value in the unlocking current generating section at each current computing moment, wherein the computing formula is as follows:
wherein ,for maximum unlocking current, +.>For differential current sampling, ">A. B, C the transformer is three-phase, [ T-T ] Σ ,t]Generating an unlocking current interval, wherein T is the current calculation time, and T Σ Generating an unlocking current interval time length;
determining the maximum floating threshold current according to the maximum value of the absolute value of the differential current sampling value in the generated floating threshold interval at each current calculation time, wherein the calculation formula is as follows:
wherein ,for maximum floating threshold current +.>For differential current sample value, [ t ] 0 ,t-T Σ ) To generate a floating threshold interval, t 0 For starting time, T is the current calculation time, T Σ Generating an unlocking current interval time length;
determining the floating threshold current at each current computing moment according to the differential current sampling value corresponding to the maximum unlocking current at each current computing moment and the differential current sampling value corresponding to the maximum floating threshold current;
and determining the unlocking current of each current computing moment according to the differential current sampling value of each sampling point in the generated unlocking current interval of each current computing moment and the maximum unlocking current.
6. The method of claim 5, wherein determining the floating threshold current for each present computing time based on the differential current sample value for the maximum unlock current and the differential current sample value for the maximum floating threshold current for each present computing time comprises:
Under the condition that the differential current sampling value corresponding to the maximum unlocking current and the differential current sampling value corresponding to the maximum floating threshold current at each current calculation time meet an extremum criterion, the floating threshold current at the current calculation time is the maximum floating threshold current, wherein the extremum criterion is as follows:
wherein ,for the differential current sampling value corresponding to the maximum unlocking current,/->A. B, C is three-phase of transformer, +.>The differential current sampling value corresponding to the maximum floating threshold current is obtained;
under the condition that the differential current sampling value corresponding to the maximum unlocking current and the differential current sampling value corresponding to the maximum floating threshold current at each current calculation time do not meet an extremum criterion, the floating threshold current at the current calculation time is:
wherein ,for floating threshold current, ">For maximum floating threshold current +.>Is the maximum unlocking current.
7. The method of claim 5, wherein the step of removing the inrush current blocking criteria is:
wherein ,for unlocking the current +.>For floating threshold current, ">A. B, C is three-phase of transformer, +.>To generate an integration result of differential current sampling values in the unlock current interval, n is the number of sampling points in the unlock current interval.
8. An implementation device for releasing inrush current blocking of a transformer is characterized by comprising:
the calculation module is used for calculating differential current sampling values of the transformer corresponding to sampling points at intervals of a first preset time period in real time according to the current sampling values of each side of the transformer;
the first determining module is used for determining the starting moment of the starting criterion under the condition that the differential current sampling value meets the preset starting criterion;
the second determining module is used for determining an unlocking current interval and a floating threshold interval generated at each current calculation time in a power frequency period according to the starting time and the differential current sampling value at the starting time;
the third determining module is used for determining unlocking current and floating threshold current at each current computing moment according to the generated unlocking current interval and the differential current sampling value of the generated floating threshold interval;
and the fourth determining module is used for determining that the transformer releases the excitation surge current locking under the condition that the unlocking current and the floating threshold current at any current calculation moment meet a preset excitation surge current releasing locking criterion.
9. A computer readable storage medium, characterized in that the storage medium stores a computer program for executing the method of any of the preceding claims 1-7.
10. An electronic device, the electronic device comprising:
a processor;
a memory for storing the processor-executable instructions;
the processor is configured to read the executable instructions from the memory and execute the instructions to implement the method of any of the preceding claims 1-7.
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