Substation main transformer three-phase asymmetric relay protection anomaly analysis method and device

Abstract

The invention provides a transformer substation main transformer three-phase asymmetric relay protection anomaly analysis method and device, and relates to the field of power electronics, and the method comprises the steps: determining a verification mode, relay protection monitoring parameters and a to-be-verified working condition according to the type of relay protection; under each to-be-checked working condition, executing a check value determination operation, and determining a check value of the relay protection monitoring parameter corresponding to each to-be-checked working condition; determining whether the relay protection is abnormal or not based on each checking value, the set value of the relay protection monitoring parameter and the checking mode; the check value determination operation comprises the steps of determining to-be-adjusted parameters of a pre-constructed electromagnetic transient analysis model; performing an iterative optimization operation on the to-be-adjusted parameter, and determining an optimal value of the to-be-adjusted parameter, the optimal value of the to-be-adjusted parameter being used for adjusting the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the to-be-checked operation condition; and determining a relay protection check value of the to-be-checked operation condition based on the optimal value and an electromagnetic transient analysis model.

Description

Technical Field

[0001] The present application belongs to the field of power electronics technology, and in particular to the field of transformer technology. Specifically, the present application relates to a method and device for analyzing abnormality of relay protection of a three-phase asymmetric main transformer of a substation. Background Art

[0002] The main transformers of 500kV and above in the substation mainly use three-phase split autotransformers. When a phase transformer of the main transformer is damaged, it is necessary to replace it with a single-phase spare transformer with the same voltage ratio, short-circuit impedance and wiring group. If there is no single-phase spare transformer on site and the main transformer needs to be put back into operation as soon as possible, temporary measures need to be taken, that is, the transformer of the faulty phase of the main transformer is temporarily replaced with a similar single-phase transformer. In this case, the relevant parameters of the single-phase transformer are not consistent with the original transformer phases.

[0003] Moreover, considering the production cycle of the spare transformer and other factors, it usually takes half a year to a year to replace the new transformer with the same parameters as the original transformer in actual engineering. Therefore, during this period of temporary measures, the substation will face the problem of asymmetric three-phase parameters of the main transformer. Summary of the invention

[0004] In response to at least one problem existing in the prior art, the present application provides a method and device for analyzing the abnormality of relay protection of a three-phase asymmetric main transformer of a substation, which can verify the adaptability of various types of relay protection in the substation where the three-phase asymmetric transformer is located, and prevent the false operation of the relay protection device from affecting the power grid.

[0005] According to a first aspect of the present application, a method for analyzing abnormal relay protection of a three-phase asymmetry of a main transformer in a substation is provided, the method comprising:

[0006] According to the type of relay protection, determine the verification method, relay protection monitoring parameters and working conditions to be verified;

[0007] Under each of the working conditions to be verified, a verification value determination operation is performed to determine the verification value of the relay protection monitoring parameter corresponding to each of the operating conditions to be verified;

[0008] Based on each of the calibration values, the set value of the relay protection monitoring parameter and the calibration method, determining whether the relay protection has an abnormality;

[0009] The calibration value determination operation includes:

[0010] Determine the parameters to be adjusted of the pre-built electromagnetic transient analysis model;

[0011] Performing an iterative optimization operation on the parameter to be adjusted to determine an optimal value of the parameter to be adjusted, wherein the optimal value of the parameter to be adjusted is used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the operating condition to be verified;

[0012] Based on the optimal value and the electromagnetic transient analysis model, the relay protection verification value of the operating condition to be verified is determined.

[0013] In some optional aspects of this embodiment, the step of constructing the electromagnetic transient analysis model includes:

[0014] Obtain the power system topology of the substation;

[0015] Obtaining preset modeling parameters of the substation, wherein the preset modeling parameters include reference capacity, reference voltage, impedance per unit value of each voltage level under the maximum operation mode, power supply values ​​of the opposite sides of each line, and three-phase asymmetric transformer parameters;

[0016] Based on the power system topology and the preset modeling parameters, the electromagnetic transient analysis model is constructed, wherein the electromagnetic transient analysis model is used to simulate the substation.

[0017] In some optional methods of this embodiment, the types of relay protection include zero-sequence protection, differential quick-break protection, ratio differential protection and main transformer overexcitation protection, and the verification method includes maximum value verification and minimum value verification; wherein, according to the type of relay protection, determining the verification method, relay protection setting value and working condition to be verified includes:

[0018] In response to determining that the type of the relay protection is the zero-sequence protection, the calibration method is determined to be the maximum value calibration; the operating conditions to be calibrated include normal operating conditions, transformer tap adjustment conditions, single line fault conditions and double line fault conditions, and the relay protection monitoring parameter is zero-sequence current.

[0019] In some optional methods of this embodiment, the verification method includes maximum value verification and minimum value verification, and determining whether the relay protection is abnormal based on each of the verification values, the set value of the relay protection monitoring parameter and the verification method includes:

[0020] In response to determining that the calibration mode is the maximum value calibration, determining the maximum value among the calibration values, and comparing the maximum value with the set value to determine whether the maximum value is less than or equal to the set value;

[0021] In response to the determination being yes, determining that there is no abnormality in the relay protection;

[0022] In response to the determination being no, determining that an abnormality exists in the relay protection;

[0023] In response to determining that the calibration mode is the minimum value calibration, determining a minimum value among the calibration values, and comparing the minimum value with the set value to determine whether the minimum value is greater than or equal to the set value;

[0024] In response to the determination being yes, determining that there is no abnormality in the relay protection;

[0025] In response to a negative determination, it is determined that an abnormality exists in the relay protection.

[0026] In some optional manners of this embodiment, determining the parameters to be adjusted of the pre-built electromagnetic transient analysis model includes:

[0027] determining a current power flow distribution of the electromagnetic transient analysis model;

[0028] Determining the parameter to be adjusted based on the current power flow distribution and the power flow distribution of the working condition to be verified;

[0029] The parameters to be adjusted include multiple simulation values, and the steps of iterative optimization operation include:

[0030] Determining the simulation value of the target electrical quantity corresponding to the simulation value of each parameter to be adjusted in sequence, until it is determined that the Euclidean distance between the simulation value of the target electrical quantity and the theoretical value of the target electrical quantity is less than a preset distance;

[0031] The simulation value of the target electrical quantity whose Euclidean distance from the theoretical value of the target electrical quantity is less than a preset distance is determined as the optimal value of the parameter to be adjusted.

[0032] In some optional aspects of this embodiment, the parameter to be adjusted is an m-dimensional column vector, the target electrical quantity is an n-dimensional column vector, and the iterative optimization operation is configured to be implemented based on a neural network, wherein:

[0033] The neural network includes an input layer, an output layer and a hidden layer, wherein the number of neural units in the input layer is p, which is the sum of m and n; the number of neural units in the output layer is m.

[0034] According to a second aspect of the present application, a device for analyzing abnormality of relay protection of a main transformer of a substation with three-phase asymmetry is also provided, the device comprising:

[0035] A first determination module is configured to determine a verification method, relay protection monitoring parameters and a working condition to be verified according to the type of relay protection;

[0036] A calibration value determination module is configured to perform a calibration value determination operation under each of the to-be-calibrated operating conditions to determine the calibration value of the relay protection monitoring parameter corresponding to each of the to-be-calibrated operating conditions;

[0037] an abnormality determination module, configured to determine whether the relay protection has an abnormality based on each of the verification values, the set value of the relay protection monitoring parameter and the verification method;

[0038] Wherein, the calibration value determination module comprises:

[0039] A to-be-adjusted parameter determination unit, configured to determine the to-be-adjusted parameters of the pre-built electromagnetic transient analysis model;

[0040] an iterative optimization unit, configured to perform an iterative optimization operation on the parameter to be adjusted to determine an optimal value of the parameter to be adjusted, wherein the optimal value of the parameter to be adjusted is used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the operating condition to be verified;

[0041] The relay protection verification value determination unit is configured to determine the relay protection verification value of the operating condition to be verified based on the optimal value and the electromagnetic transient analysis model.

[0042] In some optional aspects of this embodiment, a model building module is further included, and the model building module includes:

[0043] A topology acquisition unit is configured to acquire a power system topology of the substation;

[0044] A modeling parameter acquisition unit is configured to acquire preset modeling parameters of the substation, wherein the preset modeling parameters include a reference capacity, a reference voltage, a per-unit impedance value of each voltage level under a maximum operating mode, a value of the opposite side power supply of each line, and parameters of a three-phase asymmetric transformer;

[0045] The model building unit is configured to build the electromagnetic transient analysis model based on the power system topology and the preset modeling parameters, wherein the electromagnetic transient analysis model is used to simulate the substation.

[0046] In some optional aspects of this embodiment, the verification method includes maximum value verification and minimum value verification, and the abnormality determination module includes:

[0047] a maximum value checking unit, configured to, in response to determining that the checking mode is the maximum value checking, determine a maximum value among the checking values, and compare the maximum value with the set value to determine whether the maximum value is less than or equal to the set value;

[0048] In response to the determination being yes, determining that there is no abnormality in the relay protection;

[0049] In response to the determination being no, determining that an abnormality exists in the relay protection;

[0050] a minimum value checking unit, configured to, in response to determining that the checking mode is the minimum value checking, determine a minimum value among the checking values, and compare the minimum value with the set value to determine whether the minimum value is greater than or equal to the set value;

[0051] In response to the determination being yes, determining that there is no abnormality in the relay protection;

[0052] In response to a negative determination, it is determined that an abnormality exists in the relay protection.

[0053] In some optional aspects of this embodiment, the to-be-adjusted parameter determination unit includes:

[0054] a current power flow distribution determination subunit, configured to determine the current power flow distribution of the electromagnetic transient analysis model;

[0055] Determining the parameter to be adjusted based on the current power flow distribution and the power flow distribution of the working condition to be verified;

[0056] The parameter to be adjusted includes a plurality of simulation values, and the iterative optimization unit includes:

[0057] an iterative optimization subunit, configured to sequentially determine the simulation value of the target electrical quantity corresponding to the simulation value of each parameter to be adjusted, until it is determined that the Euclidean distance between the simulation value of the target electrical quantity and the theoretical value of the target electrical quantity is less than a preset distance;

[0058] The optimal value determination subunit is configured to determine the simulation value of the target electrical quantity whose Euclidean distance from the theoretical value of the target electrical quantity is less than a preset distance as the optimal value of the parameter to be adjusted.

[0059] According to the third aspect of the present application, there is also provided an electronic device, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps of the aforementioned method for analyzing abnormality of relay protection of a three-phase asymmetry of a main transformer of a substation are implemented.

[0060] According to the fourth aspect of the present application, a computer-readable storage medium is also provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the aforementioned method for analyzing relay protection anomalies of a substation main transformer with three-phase asymmetry are implemented.

[0061] According to the fifth aspect of the present application, a computer program product is also provided, comprising a computer program / instruction, which, when executed by a processor, implements the steps of the aforementioned method for analyzing abnormality of relay protection of a substation main transformer with three-phase asymmetry.

[0062] The present application provides a method and device for analyzing the abnormality of relay protection of asymmetric three-phase substation main transformer. After a temporary transformer (parameters are inconsistent with the original transformer) is replaced due to a fault in a phase of the substation main transformer, the adaptability of various relay protection settings is verified, which can effectively prevent false protection operations, fully ensure the selectivity of protection, and provide practical support and guarantee for the stable operation of the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0064] Figure 1 This is one of the flow charts of a method for analyzing abnormality of relay protection of a main transformer of a substation with three-phase asymmetry according to an embodiment of the present application;

[0065] Figure 2 This is a second flow chart of a method for analyzing abnormal relay protection of a substation main transformer with three-phase asymmetry according to an embodiment of the present application;

[0066] Figure 3 It is a principle flow chart of the iterative policy operation according to the embodiment of the present application;

[0067] Figure 4 A schematic diagram of iterative simulation optimization based on a neural network according to an embodiment of the present application;

[0068] Figure 5 It is a flowchart of adaptability analysis of zero-sequence protection according to an embodiment of the present application;

[0069] Figure 6 This is one of the structural diagrams of a three-phase asymmetric relay protection abnormality analysis device for a substation main transformer according to an embodiment of the present application;

[0070] Figure 7 is a structural schematic diagram of a calibration value determination module according to an embodiment of the present application;

[0071] Figure 8 A schematic diagram of the structure of a model construction determination module according to an embodiment of the present application;

[0072] Fig. 9 is a structural schematic diagram of a first determination module according to an embodiment of the present application;

[0073] Fig.10 is a structural schematic diagram of an abnormality determination module according to an embodiment of the present application;

[0074] Fig.11 A block diagram of an electronic device used to implement an embodiment of the present application. DETAILED DESCRIPTION

[0075] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0076] When a phase of the main transformer is replaced with a temporary transformer with parameters different from the original transformer, that is, the capacity, rated voltage, transformation ratio, short-circuit impedance and other parameters of the single-phase transformer are different from the parameters of each phase of the original transformer, it will cause the three-phase asymmetry of the main transformer. In this case, it is necessary to check the adaptability of various types of relay protection in the substation where this transformer is located to prevent the false operation of the relay protection device from affecting the power grid.

[0077] In view of this, an embodiment of the present application provides a method for analyzing abnormal relay protection of a three-phase asymmetric transformer in a substation, such as Figure 1 As shown, the method includes:

[0078] Step 10: According to the type of relay protection, determine the verification method, relay protection monitoring parameters and working conditions to be verified.

[0079] It should be understood that the relay protection of the power system is a device for the safe operation of the power system. The relay protection device is an automatic device that sends out signals in time when the power grid, power plant, substation and electrical equipment have faults such as disconnection, short circuit, grounding, and overload and other abnormal operations, and automatically trips the circuit breaker to cut off the fault path. The relay protection monitoring parameters are parameters used to measure whether the relay protection is abnormal. It should be noted that when the relay protection is abnormal, it indicates that the adaptability of the relay protection has not passed.

[0080] In some embodiments, the types of relay protection include zero-sequence protection, differential quick-break protection, overcurrent protection, ratio differential protection and main transformer overexcitation protection, and the verification methods include maximum value verification and minimum value verification.

[0081] Among them, zero-sequence protection refers to the zero-sequence current, zero-sequence voltage and zero-sequence power that appear after a ground fault occurs in a large short-circuit current grounding system, and these electrical quantities are used to form a relay protection type for protecting ground short circuits; differential quick-break protection is a type of differential protection, which is mainly used to ensure rapid action and tripping when a serious fault occurs inside a motor or other equipment. When the differential current exceeds the differential quick-break setting, the device will instantaneously operate the output relay to achieve rapid protection; overcurrent protection is the most basic current protection, used to respond to short-circuit faults and serious overload faults; ratio differential protection is a protection that compares the size and direction of the current at both ends of the generator, called ratio-braked longitudinal differential protection; main transformer overexcitation protection refers to when the neutral voltage of the transformer is greater than the rated value when the load on the main transformer remains unchanged, the protection device is used to prevent equipment damage caused by overexcitation.

[0082] The maximum value check is a method of comparing the maximum value with the set value, and the minimum value check is a method of comparing the minimum value with the set value.

[0083] In some embodiments, when it is determined that the type of the relay protection is the zero-sequence protection, the calibration method is determined to be the maximum value calibration; the operating conditions to be calibrated include normal operating conditions, transformer tap adjustment conditions, single line fault conditions and double line fault conditions, and the relay protection monitoring parameter is zero-sequence current.

[0084] In some embodiments, when it is determined that the type of the relay protection is the differential quick-break protection, the calibration method is determined to be the minimum value calibration; the operating conditions to be calibrated include the maximum operating mode conditions and the minimum operating mode conditions, and the relay protection monitoring parameters are the currents on each side of the transformer.

[0085] In some embodiments, when it is determined that the type of the relay protection is the ratio differential protection, the calibration method is determined to be the minimum value calibration of the current difference; the operating condition to be calibrated includes the minimum operating mode condition, and the relay protection monitoring parameter is the current on each side of the transformer.

[0086] In some embodiments, when it is determined that the type of the relay protection is the main transformer overexcitation protection, the calibration method is determined to be the maximum value calibration; the operating condition to be calibrated includes the transformer tap adjustment condition, and the relay protection monitoring parameter is the transformer voltage.

[0087] It should be noted that the maximum operating mode and the minimum operating mode are two important operating states in the power system, which are mainly used in power system flow and stability calculations.

[0088] The maximum operation mode means that when the system is running in this mode, the input power capacity is the largest and the equivalent impedance of the system is the smallest, so the short-circuit current generated after a short circuit occurs is the largest. This operation mode is usually used to verify the stability of the selected electrical equipment to ensure that the equipment can operate normally under the maximum load.

[0089] The minimum operation mode means that when the system is running in this mode, the power supply capacity is the smallest and the equivalent impedance of the system is the largest, so the short-circuit current generated after a short circuit occurs is the smallest. This operation mode is mainly used to verify the sensitivity of the relay protection device to ensure that the relay protection device can operate correctly under the minimum load.

[0090] Step 20: Under each of the working conditions to be verified, a verification value determination operation is performed to determine the verification value of the relay protection monitoring parameter corresponding to each of the operating conditions to be verified.

[0091] In this step, after the working conditions to be verified are determined, it is necessary to determine the verification values ​​of the relay protection monitoring parameters under each working condition to be verified.

[0092] For example, when the type of relay protection is zero-sequence protection, the operating conditions to be verified include normal operating conditions, transformer tap adjustment conditions, single-line fault conditions, and double-line fault conditions; the relay protection monitoring parameter is zero-sequence current; it is necessary to determine the verification values ​​of zero-sequence current under normal operating conditions, transformer tap adjustment conditions, single-line fault conditions, and double-line fault conditions, respectively.

[0093] It should also be noted that there may be multiple calibration values ​​of the zero-sequence current under each condition to be verified. For example, when the main transformer is at rated load, the zero-sequence current on the high-voltage side, the zero-sequence current on the medium-voltage side, the neutral point zero-sequence current and the zero-sequence current of each line of the main transformer under each condition to be verified need to be measured.

[0094] It should be understood that before conducting an abnormal analysis of the asymmetric three-phase relay protection of the substation main transformer, it is necessary to pre-build a simulation model of the substation, namely, an electromagnetic transient analysis model. The electromagnetic transient analysis model is used to simulate the substation, and when subsequently verifying the adaptability of various types of relay protection in the substation, the flow distribution of the electromagnetic transient analysis model is adjusted to be consistent with the current operating conditions of the substation.

[0095] In some embodiments, the steps of constructing the electromagnetic transient analysis model of the present application include:

[0096] First, the power system topology of the substation is obtained, where the power system topology of the substation refers to the power grid connecting busbars, generators, synchronous motors, load points and other components through switching devices such as circuit breakers, abstracting them into nodes that are independent of their styles, and abstracting the power lines connecting these nodes into lines, and then representing the relationship between these nodes in the form of a topological diagram.

[0097] Secondly, the preset modeling parameters of the substation are obtained, wherein the preset modeling parameters include a reference capacity, a reference voltage, the impedance per unit value of each voltage level under the maximum operating mode, the power supply values ​​on the opposite sides of each line, and three-phase asymmetric transformer parameters. The power system topology structure and the preset modeling parameters of the substation are pre-stored in the storage unit of the server and can be directly obtained.

[0098] In a specific example, the main transformer phase A of a substation is replaced with a spare transformer, for example, from a 250MVA, 525kV / 230kV / 66kV single-phase autotransformer to a 400MVA, 515kV / 230kV / 63kV single-phase autotransformer. The parameters of the original transformer are shown in Table 1, and the parameters of the spare transformer are shown in Table 2.

[0099] Table 1

[0100] model ODFS-25XXX / 500 Rated capacity 250 / 250 / 80MVA High voltage side rated voltage 525kV Short circuit impedance high-medium 13.8％ Rated voltage on medium voltage side 230kV Short circuit impedance high-low 37.88％ Low voltage side rated voltage 66kV Short circuit impedance medium-low 21.56％

[0101] Table 2

[0102] model ODFSZ-400XXX Rated capacity 400 / 400 / 120MVA High voltage side rated voltage 515kV Short circuit impedance high-medium 18.87％ Rated voltage on medium voltage side 230kV Short circuit impedance high-low 37.40％ Low voltage side rated voltage 63kV Short circuit impedance medium-low 63.27％

[0103] Taking into account the differences in capacity, transformation ratio and short-circuit impedance of the standby transformer compared with the original transformer, the substation was simulated and modeled based on the electromagnetic transient simulation tool to check the adaptability of the transformer protection after replacing the standby phase of the transformer, that is, to analyze whether the relay protection of the substation would be abnormal.

[0104] Specifically, the system equivalent is carried out on the opposite sides of the 500kV and 220kV 14 lines of the substation, and the impact of the unbalanced current on the line and main transformer protection during rated power operation is verified using the rated load under the maximum operation mode, among which:

[0105] The base capacity is 1000MVA, and the base voltage is 525kV / 230kV. Under the maximum operation mode, the impedance per unit value of each voltage level is as follows: 220kV: positive sequence reactance 0.1429, zero sequence reactance 0.1535. 500kV: positive sequence reactance 0.0351, zero sequence reactance 0.0825. The power supply equivalents of each 220kV line are the zero sequence resistance, zero sequence reactance, positive sequence resistance and positive sequence reactance of each 220kV line, which will not be described in detail here.

[0106] Finally, based on the power system topology and the preset modeling parameters, the electromagnetic transient analysis model is constructed, wherein the electromagnetic transient analysis model is used to simulate the substation. That is, a system electromagnetic transient analysis model including the main transformer, busbar and each line of the substation is established according to the actual topology and parameters of the power system.

[0107] Next, if Figure 2 As shown, the calibration value determination operation of this application is described:

[0108] Step 201: Determine the parameters to be adjusted of the pre-built electromagnetic transient analysis model.

[0109] In some embodiments, determining the parameters to be adjusted of the pre-built electromagnetic transient analysis model includes:

[0110] Determine the current power flow distribution of the electromagnetic transient analysis model; and determine the parameter to be adjusted based on the current power flow distribution and the power flow distribution of the working condition to be verified.

[0111] Specifically, the current power flow distribution of the electromagnetic transient analysis model, that is, the current operating condition, is determined; based on the current operating condition and the operating condition to be verified, the parameters that need to be adjusted, that is, the parameters to be adjusted, are determined.

[0112] Step 202: perform an iterative optimization operation on the parameter to be adjusted to determine the optimal value of the parameter to be adjusted, wherein the optimal value of the parameter to be adjusted is used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the operating condition to be verified.

[0113] In this step, the power flow distribution in the electromagnetic transient analysis model is adjusted according to the actual operating power flow of the power system (the power flow distribution of the operating condition to be verified) so that the two are as consistent as possible. Specifically, an iterative optimization operation is performed on the parameter to be adjusted to determine the optimal value of the parameter to be adjusted. The optimal value is used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the operating condition to be verified.

[0114] The parameters to be adjusted include multiple simulation values, and the steps of iterative optimization operation include:

[0115] S1. Determine the simulation value of the target electrical quantity corresponding to the simulation value of each parameter to be adjusted in sequence, until it is determined that the Euclidean distance between the simulation value of the target electrical quantity and the theoretical value of the target electrical quantity is less than a preset distance.

[0116] S2. Determine the simulation value of the target electrical quantity whose Euclidean distance from the theoretical value of the target electrical quantity is less than a preset distance as the optimal value of the parameter to be adjusted.

[0117] In the present application, the simulation value of the target electrical quantity corresponding to the simulation value of each parameter to be adjusted is determined in turn, and the Euclidean distance between the simulation value of the target electrical quantity and the theoretical value of the target electrical quantity is calculated, until it is determined that the Euclidean distance between the simulation value of the target electrical quantity and the theoretical value of the target electrical quantity is less than a preset distance. The simulation value of the target electrical quantity whose Euclidean distance with the theoretical value of the target electrical quantity is less than the preset distance is determined as the optimal value of the parameter to be adjusted.

[0118] In a specific example, the model reference adaptive identification method is used to optimize the simulation parameters in the electromagnetic transient analysis model. The principle is as follows Figure 3 As shown, by adjusting the simulation control parameters, the output results of the simulation model are made close to the given ideal indicators. When the output deviation is stabilized within a very small range, the identification is considered to be completed. At this time, the simulation control parameters can be regarded as the ideal simulation parameters of the ideal model.

[0119] When adjusting the power flow distribution in the electromagnetic transient analysis model, it is actually necessary to adjust the parameters of each electrical quantity in the electromagnetic transient analysis model. The main simulation control parameters that need to be adjusted (i.e. the aforementioned parameters to be adjusted) are the voltage amplitude and phase angle of each node, the active power and reactive power of the equivalent power source, the active power and reactive power of the load, etc. The target electrical quantity is the active power and reactive power of each line. Figure 3 The ideal performance index is the theoretical value of the target electrical quantity.

[0120] The simulation control parameters that need to be adjusted are extracted from the electromagnetic transient analysis model to form an m-dimensional column vector X = [x1, x2, ..., x m ] T ; The target electrical quantity constitutes an n-dimensional column vector Y=[y1,y2,...,y n ] T The ideal value of the target electrical quantity (i.e. the actual active power and theoretical value of reactive power of each line) constitutes the vector Y z =[y 1z ,y 2z ,...,y nz ] T The threshold ε is set, that is, the preset distance. When the Euclidean distance between the theoretical value of the target electrical quantity and the process value (i.e., the simulation value) in the n-dimensional space is less than ε during the simulation control parameter adjustment process, it is considered that the operation flow adjustment is completed, that is:

[0121]

[0122] At this time, there must be a group of X z =[x 1z ,x 2z ,...,x mz ]T With Y z Correspondingly, X z is called the ideal simulation parameter, that is, the optimal value of the parameter to be adjusted. It should be understood that X gradually approaches X z The process requires multiple iterations of simulation to solve the electromagnetic transient analysis model.

[0123] In some optional aspects of this embodiment, the parameter to be adjusted is an m-dimensional column vector, the target electrical quantity is an n-dimensional column vector, and the iterative optimization operation is configured to be implemented based on a neural network, wherein:

[0124] The neural network includes an input layer, an output layer and a hidden layer, wherein the number of neural units in the input layer is p, which is the sum of m and n; the number of neural units in the output layer is m.

[0125] In order to improve computing efficiency and reduce the number of simulation iterations, the specific ideal simulation parameter optimization algorithm can adopt the neural network method to make the simulation control parameters close to the ideal simulation parameters. Among them, the neural network has the advantages of high dimensionality, wide connectivity and adaptability. As long as the learning samples of the relevant electromagnetic transient analysis model and the initial values ​​of the simulation control parameters and the target electrical quantities under the corresponding working conditions (that is, the working conditions that need to be actually simulated) are provided, the neural network can obtain the ideal simulation parameters under the working conditions through autonomous training and learning.

[0126] Specifically, a three-layer neural network with m+n input units and m output units can be used. When a signal is input, it first reaches the hidden layer node, and after the action function, the output information of the hidden layer unit is transmitted to the output layer unit, and the output result is given after processing. If the output layer cannot get the expected output, the error of the output signal is returned along the original connection path, and the error is minimized (converged) by correcting the weights of the neurons in each layer.

[0127] The specific process is as follows: determine the initial parameters of the neural network, input the neural network learning samples, perform parameter preprocessing, and form a neural network simulation parameter knowledge base through neural network training and learning; when approximating the ideal simulation parameters, input the initial simulation control parameters of this simulation modeling and the process values ​​of the target electrical quantities under the corresponding working conditions (that is, the initial values ​​of the simulation control parameters and the target electrical quantities under a certain actual working condition that needs to be simulated) into the neural network, perform inference calculations based on the neural network parameter knowledge base, and form the ideal simulation parameters under this working condition. The model of this method is as follows Figure 4 shown.

[0128] In this embodiment, the neural network design and implementation steps are as follows:

[0129] (1) Determine the initial parameters of the neural network

[0130] Among them, the number of neural units in the input layer is m+n, which is related to different electromagnetic transient analysis models, and specifically is consistent with the sum of the simulation control parameters (parameters to be adjusted) and the target electrical quantities in the electromagnetic transient analysis model; the number of neural units in the output layer is m, which is related to different electromagnetic transient analysis models, and specifically is consistent with the number of simulation control parameters in the electromagnetic transient analysis model; the number of hidden layers is 1; the number of neural units in the hidden layer can be determined by itself according to the structure of the neural network, and this application does not limit this.

[0131] (2) Determination of input vector. Determine the input vector of the neural network as an m+n-dimensional column vector T = [x1, x2, ..., x m ,y 1z ,y 2z ,...,y nz ] T , that is, the simulation control parameters of the electromagnetic transient analysis model and the target electrical quantity under the corresponding working condition. Since the neural network requires that the input must be in the interval [0, 1], it is necessary to normalize the input information.

[0132] (3) Select learning samples for neural network learning. The known ideal simulation parameters of the electromagnetic transient analysis model under various known operating modes of the substation and the target electrical quantities under the corresponding working conditions are selected as learning samples for the neural network to learn. These samples should reflect the actual situation under various electrical operating modes of the substation as much as possible. The learning process of the neural network is the process of determining the connection weights of the network and repeatedly correcting the errors based on the data samples.

[0133] (4) Determine the action function. The neural network algorithm requires that the first-order derivative of the action function of each layer is differentiable everywhere. Usually, a nonlinear Sigmoid function can be selected.

[0134] (5) Establish an evaluation knowledge base. Through sample learning, determine the weights of neurons in each layer of the neural network and the output threshold.

[0135] (6) Input the initial value of the simulation control parameter and the target electrical quantity under a certain actual working condition that needs to be simulated and calculated. The neural network outputs the m-dimensional ideal simulation parameters that need to be obtained under the working condition, that is, the optimal value of the parameter to be adjusted.

[0136] Step 203: Determine the relay protection verification value of the operating condition to be verified based on the optimal value and the electromagnetic transient analysis model.

[0137] In this step, when the current power flow distribution of the electromagnetic transient analysis model is adjusted to be consistent with the power flow distribution of the operating condition to be verified, the relay protection verification value of the operating condition to be verified is determined.

[0138] Step 30: Determine whether the relay protection has an abnormality based on the calibration values, the set values ​​of the relay protection monitoring parameters and the calibration method.

[0139] It should be noted that it is necessary to determine the calibration values ​​of the relay protection monitoring parameters under all working conditions to be calibrated, so as to determine whether the relay protection has an abnormality based on each of the calibration values, the set values ​​of the relay protection monitoring parameters and the calibration method.

[0140] In some optional methods of this embodiment, the line zero-sequence current protection verification needs to be carried out in the following two cases: when a single main transformer is in operation and when the main transformers are in parallel operation. In each case, the verification needs to be carried out under the following working conditions: in normal mode, when the transformer tap is adjusted, and when N-1 or N-2 faults occur in each line of the substation. Among them, when N-1 or N-2 faults occur in each line (double-circuit line), it is necessary to disconnect the corresponding line in the electromagnetic transient analysis model, and adjust the flow distribution of the electromagnetic transient analysis model according to the actual flow conditions; when the transformer tap is adjusted, it is also necessary to adjust the voltage values ​​on each side of the transformer in the electromagnetic transient analysis model according to the actual main transformer tap gear on site, and adjust the model transmission power according to the actual flow.

[0141] Each of the above working conditions requires the zero-sequence current to be checked in order to find the most demanding working condition for protection, that is, the working condition with the largest zero-sequence current of the line. When the zero-sequence current under this working condition is still less than the set value of the line zero-sequence protection, it will not cause the line zero-sequence protection to malfunction, and it is determined that the adaptability analysis of the line zero-sequence protection of the substation has passed the verification and there is no abnormality. Among them, the adaptability process of the line zero-sequence protection is as follows Figure 5 As shown, specifically:

[0142] Start adaptability analysis; establish an electromagnetic transient analysis model; determine the operating condition, i.e., the condition to be verified; optimize simulation parameters and adjust the model operating flow; determine whether the Euclidean distance between Y and Yz is less than ε; if so, obtain the zero-sequence current in the electromagnetic transient analysis model; if not, continue to optimize simulation parameters and adjust the model operating flow; determine whether the obtained zero-sequence current is greater than the calculated zero-sequence current, if so, save the calculation result; if not, abandon the calculation result; determine whether the operating condition has been traversed, if not, determine the zero-sequence current of the next operating condition; if yes, determine whether the calculation result is less than the protection setting, if so, pass the zero-sequence protection adaptability analysis; if not, fail the zero-sequence protection adaptability analysis.

[0143] In some embodiments, when it is determined that the calibration method is the maximum value calibration, the maximum value of the calibration values ​​is determined, and the maximum value is compared with the set value to determine whether the maximum value is less than or equal to the set value, wherein:

[0144] When it is determined that the maximum value is less than or equal to the set value, it is determined that there is no abnormality in the relay protection, that is, the relay protection adaptability analysis is passed; when it is determined that the maximum value is greater than the set value, it is determined that there is an abnormality in the relay protection, that is, the relay protection adaptability analysis is not passed.

[0145] In some embodiments, when it is determined that the calibration method is the minimum value calibration, the minimum value among the calibration values ​​is determined, and the minimum value is compared with the set value to determine whether the minimum value is greater than or equal to the set value, wherein:

[0146] When it is determined that the minimum value is greater than or equal to the set value, it is determined that there is no abnormality in the relay protection, that is, the relay protection adaptability analysis is passed; when it is determined that the minimum value is less than the set value, it is determined that there is an abnormality in the relay protection, that is, the relay protection adaptability analysis is not passed.

[0147] This application can effectively prevent false operation of protection, fully ensure the selectivity of protection, and provide practical support and guarantee for the stable operation of the power grid by verifying the adaptability of various relay protection settings after a temporary transformer (with parameters inconsistent with the original transformer) is replaced due to a fault in a phase of the main transformer of the substation.

[0148] It should be noted that the acquisition, storage, use and processing of data in the technical solution of this application are in compliance with the relevant provisions of laws and regulations.

[0149] Based on the same inventive concept, the embodiment of the present application also provides a three-phase asymmetric relay protection abnormality analysis device for a substation main transformer, which can be used to implement the method described in the above embodiment, as described in the following embodiment. Since the principle of the problem solved by the three-phase asymmetric relay protection abnormality analysis device for a substation main transformer is similar to a three-phase asymmetric relay protection abnormality analysis method for a substation main transformer, the implementation of a three-phase asymmetric relay protection abnormality analysis device for a substation main transformer can refer to the implementation of a three-phase asymmetric relay protection abnormality analysis method for a substation main transformer, and the repetitions are not repeated. As used below, the term "unit" or "module" can implement a combination of software and / or hardware for a predetermined function. Although the system described in the following embodiments is preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceived.

[0150] like Figure 6 As shown, the three-phase asymmetric relay protection abnormality analysis device of the main transformer of the substation comprises:

[0151] The first determination module 601 is configured to determine the verification mode, the relay protection monitoring parameters and the working condition to be verified according to the type of relay protection;

[0152] The calibration value determination module 602 is configured to perform a calibration value determination operation under each of the to-be-calibrated operating conditions to determine the calibration value of the relay protection monitoring parameter corresponding to each of the to-be-calibrated operating conditions;

[0153] The abnormality determination module 603 is configured to determine whether the relay protection has an abnormality based on each of the verification values, the set value of the relay protection monitoring parameter and the verification method;

[0154] Among them, Figure 7 As shown, the calibration value determination module includes:

[0155] The parameter-to-be-adjusted determining unit 6021 is configured to determine the parameter to be adjusted of the pre-built electromagnetic transient analysis model;

[0156] An iterative optimization unit 6022 is configured to perform an iterative optimization operation on the parameter to be adjusted to determine an optimal value of the parameter to be adjusted, wherein the optimal value of the parameter to be adjusted is used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the operating condition to be verified;

[0157] The relay protection verification value determination unit 6023 is configured to determine the relay protection verification value of the operating condition to be verified based on the optimal value and the electromagnetic transient analysis model.

[0158] In some optional embodiments of this embodiment, Figure 8 The diagram also includes a model building module 604, wherein the model building module 604 includes:

[0159] A topology acquisition unit 6041 is configured to acquire a power system topology of a substation;

[0160] The modeling parameter acquisition unit 6042 is configured to acquire preset modeling parameters of the substation, wherein the preset modeling parameters include reference capacity, reference voltage, impedance per unit value of each voltage level under the maximum operation mode, power supply value of each line opposite side, and three-phase asymmetric transformer parameters;

[0161] The model building unit 6043 is configured to build the electromagnetic transient analysis model based on the power system topology and the preset modeling parameters, wherein the electromagnetic transient analysis model is used to simulate the substation.

[0162] In some optional modes of this embodiment, the types of relay protection include zero-sequence protection, differential quick-break protection, ratio differential protection and main transformer overexcitation protection, and the verification mode includes maximum value verification and minimum value verification; wherein, Fig. 9 As shown, the first determination module 601 includes:

[0163] The zero-sequence protection determination unit 6011 is configured to determine that the calibration method is the maximum value calibration in response to determining that the type of the relay protection is the zero-sequence protection; the operating conditions to be calibrated include normal operating conditions, transformer tap adjustment conditions, single line fault conditions and double line fault conditions, and the relay protection monitoring parameter is the zero-sequence current.

[0164] The differential quick-break protection determination unit 6012 is configured to, in response to the type of the relay protection being the differential quick-break protection, determine that the verification mode is the minimum verification; the working condition to be verified includes the maximum operating mode working condition and the minimum operating mode working condition, and the relay protection monitoring parameter is the current on each side of the transformer;

[0165] The ratio differential protection determination unit 6013 is configured to, in response to determining that the type of the relay protection is the ratio differential protection, determine that the verification mode is the minimum value verification of the current difference; the working condition to be verified includes the minimum operating mode working condition, and the relay protection monitoring parameter is the current on each side of the transformer;

[0166] The main transformer overexcitation protection determination unit 6014 is configured to determine that the type of the relay protection is the main transformer overexcitation protection, and to determine that the verification method is the maximum value verification; the working condition to be verified includes the transformer tap adjustment working condition, and the relay protection monitoring parameter is the transformer voltage.

[0167] In some optional methods of this embodiment, the verification method includes maximum value verification and minimum value verification, such as Fig.10 As shown, the abnormality determination module 603 includes:

[0168] A maximum value checking unit 6031 is configured to, in response to determining that the checking mode is the maximum value checking, determine a maximum value among the checking values, and compare the maximum value with the set value to determine whether the maximum value is less than or equal to the set value;

[0169] In response to the determination being yes, determining that there is no abnormality in the relay protection;

[0170] In response to the determination being no, determining that an abnormality exists in the relay protection;

[0171] A minimum value checking unit 6032 is configured to, in response to determining that the checking mode is the minimum value checking, determine a minimum value among the checking values, and compare the minimum value with the set value to determine whether the minimum value is greater than or equal to the set value;

[0172] In response to the determination being yes, determining that there is no abnormality in the relay protection;

[0173] In response to a negative determination, it is determined that an abnormality exists in the relay protection.

[0174] In some optional aspects of this embodiment, the to-be-adjusted parameter determination unit includes:

[0175] a current power flow distribution determination subunit, configured to determine the current power flow distribution of the electromagnetic transient analysis model;

[0176] Determining the parameter to be adjusted based on the current power flow distribution and the power flow distribution of the working condition to be verified;

[0177] The parameter to be adjusted includes a plurality of simulation values, and the iterative optimization unit includes:

[0178] an iterative optimization subunit, configured to sequentially determine the simulation value of the target electrical quantity corresponding to the simulation value of each parameter to be adjusted, until it is determined that the Euclidean distance between the simulation value of the target electrical quantity and the theoretical value of the target electrical quantity is less than a preset distance;

[0179] The optimal value determination subunit is configured to determine the simulation value of the target electrical quantity whose Euclidean distance from the theoretical value of the target electrical quantity is less than a preset distance as the optimal value of the parameter to be adjusted.

[0180] In some optional aspects of this embodiment, the parameter to be adjusted is an m-dimensional column vector, the target electrical quantity is an n-dimensional column vector, and the iterative optimization operation is configured to be implemented based on a neural network, wherein:

[0181] The neural network includes an input layer, an output layer and a hidden layer, wherein the number of neural units in the input layer is p, which is the sum of m and n; the number of neural units in the output layer is m.

[0182] According to an embodiment of the present disclosure, the present disclosure also provides an electronic device, a readable storage medium and a computer program product.

[0183] An electronic device comprises: at least one processor; and a memory connected to the at least one processor in communication; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the steps of a method for analyzing abnormality of relay protection of a substation main transformer with three-phase asymmetry of the aforementioned embodiment.

[0184] A non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to cause a computer to execute the steps of a method for analyzing abnormal relay protection of a substation main transformer with three-phase asymmetry in the aforementioned embodiment.

[0185] A computer program product includes a computer program / instruction, which, when executed by a processor, implements the steps of a method for analyzing abnormality of relay protection of a main transformer of a substation with three-phase asymmetry in the aforementioned embodiment.

[0186] Fig.11 A schematic block diagram of an example electronic device 900 that can be used to implement an embodiment of the present disclosure is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present disclosure described and / or required herein.

[0187] like Fig.11 As shown, the device 900 includes a computing unit 901, which can perform various appropriate actions and processes according to a computer program stored in a read-only memory (ROM) 902 or a computer program loaded from a storage unit 908 into a random access memory (RAM) 903. In the RAM 903, various programs and data required for the operation of the device 900 can also be stored. The computing unit 901, the ROM 902, and the RAM 903 are connected to each other via a bus 904. An input / output (I / O) interface 905 is also connected to the bus 904.

[0188] A number of components in the device 900 are connected to the I / O interface 905, including: an input unit 906, such as a keyboard, a mouse, etc.; an output unit 907, such as various types of displays, speakers, etc.; a storage unit 908, such as a disk, an optical disk, etc.; and a communication unit 909, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 909 allows the device 900 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0189] The computing unit 901 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the computing unit 901 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, digital signal processors (DSPs), and any appropriate processors, controllers, microcontrollers, etc. The computing unit 901 performs the various methods and processes described above, such as a method for analyzing abnormal relay protection of a three-phase asymmetric main transformer of a substation.

[0190] For example, in some embodiments, a method for analyzing the abnormality of relay protection of a substation main transformer with three-phase asymmetry can be implemented as a computer software program, which is tangibly contained in a machine-readable medium, such as a storage unit 908. In some embodiments, part or all of the computer program can be loaded and / or installed on the device 900 via the ROM 902 and / or the communication unit 909. When the computer program is loaded into the RAM 903 and executed by the computing unit 901, one or more steps of the method for analyzing the abnormality of relay protection of a substation main transformer with three-phase asymmetry described above can be executed. Alternatively, in other embodiments, the computing unit 901 can be configured to execute a method for analyzing the abnormality of relay protection of a substation main transformer with three-phase asymmetry by any other appropriate means (for example, by means of firmware).

[0191] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0192] The program code for implementing the method of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that the program code, when executed by the processor or controller, implements the functions / operations specified in the flow chart and / or block diagram. The program code may be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0193] In the context of the present disclosure, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or equipment. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or equipment, or any suitable combination of the foregoing. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0194] To provide interaction with a user, the systems and techniques described herein can be implemented on a computer having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user can provide input to the computer. Other types of devices can also be used to provide interaction with the user; for example, the feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic input, voice input, or tactile input).

[0195] The systems and techniques described herein may be implemented in a computing system that includes back-end components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes front-end components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such back-end components, middleware components, or front-end components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), and the Internet.

[0196] A computer system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The relationship of client and server is generated by computer programs running on respective computers and having a client-server relationship with each other. The server may be a cloud server, a server of a distributed system, or a server combined with a blockchain.

[0197] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps recorded in this disclosure can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of this disclosure can be achieved, and this document is not limited here.

[0198] The above specific implementations do not constitute a limitation on the protection scope of the present disclosure. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A method for analyzing abnormal relay protection of a three-phase asymmetric main transformer in a substation, characterized in that: include: According to the type of relay protection, determine the verification method, relay protection monitoring parameters and working conditions to be verified; Under each of the working conditions to be verified, a verification value determination operation is performed to determine the verification value of the relay protection monitoring parameter corresponding to each of the operating conditions to be verified; Based on each of the calibration values, the set value of the relay protection monitoring parameter and the calibration method, determining whether the relay protection has an abnormality; The calibration value determination operation includes: Determine the parameters to be adjusted of the pre-built electromagnetic transient analysis model; Performing an iterative optimization operation on the parameter to be adjusted to determine an optimal value of the parameter to be adjusted, wherein the optimal value of the parameter to be adjusted is used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the operating condition to be verified; Based on the optimal value and the electromagnetic transient analysis model, the relay protection verification value of the operating condition to be verified is determined.

2. The relay protection abnormality analysis method according to claim 1, characterized in that: The steps of constructing the electromagnetic transient analysis model include: Obtain the power system topology of the substation; Obtaining preset modeling parameters of the substation, wherein the preset modeling parameters include reference capacity, reference voltage, impedance per unit value of each voltage level under the maximum operation mode, power supply values ​​of the opposite sides of each line, and three-phase asymmetric transformer parameters; Based on the power system topology and the preset modeling parameters, the electromagnetic transient analysis model is constructed, wherein the electromagnetic transient analysis model is used to simulate the substation.

3. The relay protection abnormality analysis method according to claim 1, characterized in that: The types of relay protection include zero-sequence protection, differential quick-break protection, ratio differential protection and main transformer overexcitation protection, and the verification mode includes maximum value verification and minimum value verification; wherein, according to the type of relay protection, the verification mode, relay protection setting value and working condition to be verified are determined, including: In response to determining that the type of the relay protection is the zero-sequence protection, the calibration method is determined to be the maximum value calibration; the operating conditions to be calibrated include normal operating conditions, transformer tap adjustment conditions, single line fault conditions and double line fault conditions, and the relay protection monitoring parameter is zero-sequence current.

4. The relay protection abnormality analysis method according to claim 1, characterized in that: The verification method includes a maximum value verification and a minimum value verification, and determining whether the relay protection is abnormal based on each of the verification values, the set value of the relay protection monitoring parameter and the verification method includes: In response to determining that the calibration mode is the maximum value calibration, determining the maximum value among the calibration values, and comparing the maximum value with the set value to determine whether the maximum value is less than or equal to the set value; In response to the determination being yes, determining that there is no abnormality in the relay protection; In response to the determination being no, determining that an abnormality exists in the relay protection; In response to determining that the calibration mode is the minimum value calibration, determining a minimum value among the calibration values, and comparing the minimum value with the set value to determine whether the minimum value is greater than or equal to the set value; In response to the determination being yes, determining that there is no abnormality in the relay protection; In response to a negative determination, it is determined that an abnormality exists in the relay protection.

5. The relay protection abnormality analysis method according to claim 1, characterized in that: The step of determining the parameters to be adjusted of the pre-built electromagnetic transient analysis model includes: determining a current power flow distribution of the electromagnetic transient analysis model; Determining the parameter to be adjusted based on the current power flow distribution and the power flow distribution of the working condition to be verified; The parameters to be adjusted include multiple simulation values, and the steps of iterative optimization operation include: Determining the simulation value of the target electrical quantity corresponding to the simulation value of each parameter to be adjusted in sequence, until it is determined that the Euclidean distance between the simulation value of the target electrical quantity and the theoretical value of the target electrical quantity is less than a preset distance; The simulation value of the target electrical quantity whose Euclidean distance from the theoretical value of the target electrical quantity is less than a preset distance is determined as the optimal value of the parameter to be adjusted.

6. The relay protection abnormality analysis method according to claim 5, characterized in that: The parameter to be adjusted is an m-dimensional column vector, the target electrical quantity is an n-dimensional column vector, and the iterative optimization operation is configured to be implemented based on a neural network, wherein: The neural network includes an input layer, an output layer and a hidden layer, wherein the number of neural units in the input layer is p, and p is the sum of m and n; the number of neural units in the output layer is m.

7. A three-phase asymmetric relay protection abnormality analysis device for a substation main transformer, characterized in that: include: A first determination module is configured to determine a verification method, relay protection monitoring parameters and a working condition to be verified according to the type of relay protection; A calibration value determination module is configured to perform a calibration value determination operation under each of the to-be-calibrated operating conditions to determine the calibration value of the relay protection monitoring parameter corresponding to each of the to-be-calibrated operating conditions; an abnormality determination module, configured to determine whether the relay protection has an abnormality based on each of the verification values, the set value of the relay protection monitoring parameter and the verification method; Wherein, the calibration value determination module comprises: A to-be-adjusted parameter determination unit, configured to determine the to-be-adjusted parameters of the pre-built electromagnetic transient analysis model; an iterative optimization unit, configured to perform an iterative optimization operation on the parameter to be adjusted to determine an optimal value of the parameter to be adjusted, wherein the optimal value of the parameter to be adjusted is used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the operating condition to be verified; The relay protection verification value determination unit is configured to determine the relay protection verification value of the operating condition to be verified based on the optimal value and the electromagnetic transient analysis model.

8. The relay protection abnormality analysis device according to claim 7, characterized in that: Also included is a model building module, the model building module comprising: A topology acquisition unit is configured to acquire a power system topology of the substation; A modeling parameter acquisition unit is configured to acquire preset modeling parameters of the substation, wherein the preset modeling parameters include a reference capacity, a reference voltage, a per-unit impedance value of each voltage level under a maximum operating mode, a value of the opposite side power supply of each line, and parameters of a three-phase asymmetric transformer; The model building unit is configured to build the electromagnetic transient analysis model based on the power system topology and the preset modeling parameters, wherein the electromagnetic transient analysis model is used to simulate the substation.

9. The relay protection abnormality analysis device according to claim 7, characterized in that: The verification method includes maximum value verification and minimum value verification, and the abnormality determination module includes: a maximum value checking unit, configured to, in response to determining that the checking mode is the maximum value checking, determine a maximum value among the checking values, and compare the maximum value with the set value to determine whether the maximum value is less than or equal to the set value; In response to the determination being yes, determining that there is no abnormality in the relay protection; In response to the determination being no, determining that an abnormality exists in the relay protection; a minimum value checking unit, configured to, in response to determining that the checking mode is the minimum value checking, determine a minimum value among the checking values, and compare the minimum value with the set value to determine whether the minimum value is greater than or equal to the set value; In response to the determination being yes, determining that there is no abnormality in the relay protection; In response to a negative determination, it is determined that an abnormality exists in the relay protection.

10. The relay protection abnormality analysis device according to claim 7, characterized in that: The to-be-adjusted parameter determination unit comprises: a current power flow distribution determination subunit, configured to determine the current power flow distribution of the electromagnetic transient analysis model; Determining the parameter to be adjusted based on the current power flow distribution and the power flow distribution of the working condition to be verified; The parameter to be adjusted includes a plurality of simulation values, and the iterative optimization unit includes: an iterative optimization subunit, configured to sequentially determine the simulation value of the target electrical quantity corresponding to the simulation value of each parameter to be adjusted, until it is determined that the Euclidean distance between the simulation value of the target electrical quantity and the theoretical value of the target electrical quantity is less than a preset distance; The optimal value determination subunit is configured to determine the simulation value of the target electrical quantity whose Euclidean distance from the theoretical value of the target electrical quantity is less than a preset distance as the optimal value of the parameter to be adjusted.

11. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the steps of the method for analyzing abnormality of relay protection of a substation main transformer with three-phase asymmetry are implemented as described in any one of claims 1 to 6.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of a method for analyzing abnormality of relay protection of a main transformer of a substation with three-phase asymmetry are implemented as described in any one of claims 1 to 6.

13. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instruction is executed by a processor, the steps of a method for analyzing abnormality of relay protection of a main transformer of a substation with three-phase asymmetry are implemented as described in any one of claims 1 to 6.

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