Method and device for analyzing abnormal relay protection of three-phase asymmetry of main transformer of substation

Abstract

The application provides a substation main transformer three-phase asymmetric relay protection abnormality analysis method and device, relates to the power electronic field, and the method comprises the following steps: according to the type of relay protection, determining the checking mode, relay protection monitoring parameters and to-be-checked working conditions; under each to-be-checked working condition, executing a checking value determination operation to determine the checking value of the relay protection monitoring parameters corresponding to each to-be-checked working condition; based on each checking value, the set value of the relay protection monitoring parameters and the checking mode, determining whether the relay protection is abnormal; the checking value determination operation comprises the following steps: determining the to-be-adjusted parameters of the pre-constructed electromagnetic transient analysis model; executing an iterative optimization operation on the to-be-adjusted parameters to determine the optimal value of the to-be-adjusted parameters, the optimal value of the to-be-adjusted parameters 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 to-be-checked working condition; based on the optimal value and the electromagnetic transient analysis model, determining the relay protection checking value of the to-be-checked working condition.

Description

Technical Field

[0001] This application belongs to the field of power electronics technology, and particularly relates to the field of transformer technology. Specifically, it relates to a method and device for analyzing relay protection anomalies in three-phase asymmetry of the main transformer in a substation. Background Technology

[0002] In substations, main transformers with voltage levels of 500kV and above primarily employ three-phase autotransformers. When a phase of the main transformer fails, a single-phase standby transformer with the same voltage ratio, short-circuit impedance, and connection group needs to be replaced. If no single-phase standby transformer is available on-site, and the main transformer needs to be put back into operation as soon as possible, temporary measures must be taken. This involves temporarily replacing the transformer of the faulty phase with a similar single-phase transformer. In this case, the relevant parameters of the new single-phase transformer will not be consistent with those of the original transformer.

[0003] Furthermore, considering factors such as the production cycle of backup transformers, in actual engineering practice, replacing the original transformer with a new one with parameters identical to the original transformer typically requires a waiting period of six months to a year. Therefore, during this period of temporary measures, the substation will face the problem of unbalanced three-phase parameters of the main transformer. Summary of the Invention

[0004] To address at least one problem in the existing technology, this application provides a method and device for analyzing relay protection anomalies in three-phase asymmetry of the main transformer in a substation. This method can verify the adaptability of various relay protection devices in the substation where the three-phase asymmetric transformer is located, and prevent the malfunction of relay protection devices from affecting the power grid.

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

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

[0007] Under each of the aforementioned operating 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 aforementioned operating conditions to be verified.

[0008] Based on the verification values, the set values ​​of the relay protection monitoring parameters, and the verification method, it is determined whether there is an abnormality in the relay protection.

[0009] The verification value determination operation includes:

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

[0011] An iterative optimization operation is performed 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 make the current power flow distribution of the electromagnetic transient analysis model consistent with the power flow distribution of the operating condition to be checked;

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

[0013] In some optional embodiments of this example, the steps for constructing the electromagnetic transient analysis model include:

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

[0015] Obtain the preset modeling parameters of the substation, wherein the preset modeling parameters include the base capacity, base voltage, per-unit impedance values ​​of each voltage level under the maximum operating mode, equivalent power supply values ​​on the opposite side of each line, and parameters of the three-phase unbalanced transformer.

[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 embodiments of this example, the types of relay protection include zero-sequence protection, differential instantaneous overcurrent protection, ratio differential protection, and main transformer overexcitation protection; the verification methods include maximum value verification and minimum value verification; wherein, determining the verification method, relay protection setpoint, and operating condition to be verified according to the type of relay protection includes:

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

[0019] In some optional embodiments of this example, the verification method includes maximum value verification and minimum value verification. Determining whether the relay protection is abnormal based on each verification value, the set value of the relay protection monitoring parameter, and the verification method includes:

[0020] In response to determining that the verification method is the maximum value verification, the maximum value among the verification 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;

[0021] In response to the determination being yes, it is determined that the relay protection is not abnormal;

[0022] If the response is negative, it is determined that the relay protection is malfunctioning.

[0023] In response to determining that the verification method is the minimum value verification, the minimum value among the verification 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;

[0024] In response to the determination being yes, it is determined that the relay protection is not abnormal;

[0025] If the response is negative, it is determined that there is an anomaly in the relay protection.

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

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

[0028] Based on the current power flow distribution and the power flow distribution of the operating condition to be checked, the parameters to be adjusted are determined;

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

[0030] The simulated values ​​of the target electrical quantities corresponding to the simulated values ​​of each of the parameters to be adjusted are determined sequentially until the Euclidean distance between the simulated value of the target electrical quantity and the theoretical value of the target electrical quantity is less than a preset distance.

[0031] The simulated 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 embodiments of this example, 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. The number of neural units in the input layer is p, where p is the sum of the numbers m and n. The number of neural units in the output layer is m.

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

[0035] The first determining module is configured to determine the verification method, relay protection monitoring parameters, and operating conditions to be verified based on the type of relay protection.

[0036] The verification value determination module is configured to perform a verification value determination operation under each of the said operating conditions to be verified, and determine the verification value of the relay protection monitoring parameter corresponding to each of the said operating conditions to be verified;

[0037] The anomaly determination module is configured to determine whether there is an anomaly in the relay protection based on each of the verification values, the set values ​​of the relay protection monitoring parameters, and the verification method.

[0038] The verification value determination module includes:

[0039] The parameter determination unit is configured to determine the parameters to be adjusted in a pre-built electromagnetic transient analysis model;

[0040] An iterative optimization unit is configured to 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 checked;

[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 embodiments of this example, a model building module is also included, the model building module comprising:

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

[0044] The modeling parameter acquisition unit is configured to acquire the preset modeling parameters of the substation, wherein the preset modeling parameters include the base capacity, base voltage, per-unit impedance values ​​of each voltage level under the maximum operating mode, the equivalent power supply values ​​of each line opposite side, and the parameters of the three-phase unbalanced 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 embodiments of this example, the verification method includes maximum value verification and minimum value verification, and the anomaly determination module includes:

[0047] The maximum value verification unit is configured to, in response to determining that the verification method is the maximum value verification, determine the maximum value among the verification values, compare the maximum value with the set value, and determine whether the maximum value is less than or equal to the set value.

[0048] In response to the determination being yes, it is determined that the relay protection is not abnormal;

[0049] If the response is negative, it is determined that the relay protection is malfunctioning.

[0050] A minimum value verification unit is configured to, in response to determining that the verification method is the minimum value verification, determine the minimum value among the verification values, compare the minimum value with the set value, and determine whether the minimum value is greater than or equal to the set value.

[0051] In response to the determination being yes, it is determined that the relay protection is not abnormal;

[0052] If the response is negative, it is determined that there is an anomaly in the relay protection.

[0053] In some optional embodiments of this example, the parameter determination unit includes:

[0054] The current power flow distribution determination sub-unit is configured to determine the current power flow distribution of the electromagnetic transient analysis model;

[0055] Based on the current power flow distribution and the power flow distribution of the operating condition to be checked, the parameters to be adjusted are determined;

[0056] The parameters to be adjusted include multiple simulation values, and the iterative optimization unit includes:

[0057] The iterative optimization subunit is configured to sequentially determine the simulation value of the target electrical quantity corresponding to the simulation value of each of the parameters 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 simulated 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 a third aspect of this application, an electronic device is also provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the aforementioned method for analyzing relay protection anomalies in three-phase asymmetry of a substation main transformer.

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

[0061] According to a fifth aspect of this application, a computer program product is also provided, including a computer program / instructions that, when executed by a processor, implement the steps of the aforementioned method for analyzing relay protection anomalies in three-phase asymmetry of a substation main transformer.

[0062] This application provides a method and device for analyzing relay protection anomalies in three-phase asymmetry of the main transformer in a substation. By replacing a temporary transformer (with parameters inconsistent with the original transformer) with a temporary transformer due to a fault in a phase of the main transformer in the substation, the adaptability of various relay protection settings can be verified. This can effectively prevent protection maloperation, fully guarantee the selectivity of protection, and provide practical support and guarantee for the stable operation of the power grid. Attached Figure Description

[0063] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0064] Figure 1 This is one of the flowcharts for a relay protection anomaly analysis method for three-phase asymmetry of a substation main transformer according to an embodiment of this application;

[0065] Figure 2 This is a second flowchart of a relay protection anomaly analysis method for three-phase asymmetry of a substation main transformer according to an embodiment of this application;

[0066] Figure 3 This is a flowchart illustrating the principle of the iterative policy operation according to the embodiments of this application;

[0067] Figure 4 This is a schematic diagram illustrating iterative simulation optimization based on a neural network according to an embodiment of this application.

[0068] Figure 5 This is a flowchart illustrating the adaptive analysis of zero-sequence protection according to an embodiment of this application;

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

[0070] Figure 7 This is a schematic diagram of the verification value determination module according to an embodiment of this application;

[0071] Figure 8 This is a schematic diagram of the structure of the module for determining the model construction according to an embodiment of this application;

[0072] Figure 9 This is a schematic diagram of the structure of the first determining module according to an embodiment of this application;

[0073] Figure 10 This is a schematic diagram of the anomaly determination module according to an embodiment of this application;

[0074] Figure 11 A block diagram of an electronic device used to implement embodiments of this application. Detailed Implementation

[0075] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort 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, turns 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 three-phase asymmetry of the main transformer. In this case, it is necessary to check the adaptability of various relay protection devices in the substation where the transformer is located to prevent the malfunction of the relay protection devices from affecting the power grid.

[0077] In view of this, one embodiment of this application provides a method for analyzing relay protection anomalies in three-phase asymmetry of the main transformer in a substation, such as... Figure 1 As shown, the method includes:

[0078] Step 10: Determine the verification method, relay protection monitoring parameters, and operating conditions to be verified based on the type of relay protection.

[0079] It should be understood that power system relay protection is a device designed to ensure the safe operation of the power system. Relay protection devices are automatic devices that promptly issue signals and cause circuit breakers to automatically trip and disconnect the fault path when faults such as open circuits, short circuits, grounding faults, or overloads occur in the power grid, power plants, substations, and electrical equipment. Relay protection monitoring parameters are used to measure whether the relay protection is abnormal. It should be noted that when the relay protection is abnormal, it indicates that the relay protection's adaptability has failed.

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

[0081] Zero-sequence protection refers to the relay protection that protects against grounding short circuits by utilizing the zero-sequence current, zero-sequence voltage, and zero-sequence power that appear after a grounding fault occurs in a grounding system with a large short-circuit current. Differential instantaneous overcurrent protection is a type of differential protection, mainly used to ensure rapid tripping when a serious fault occurs inside a motor or other equipment. When the differential current exceeds the differential instantaneous overcurrent setting, the device will instantaneously activate the output relay to achieve rapid protection. Overcurrent protection is a basic type of current protection used to respond to short-circuit faults and severe overload faults. Ratio differential protection is a type of protection that compares the magnitude and direction of the current at both ends of a generator, called ratio-restrained longitudinal differential protection. Main transformer overexcitation protection refers to the protection device used to prevent equipment damage caused by overexcitation when the transformer neutral voltage is greater than the rated value under constant load.

[0082] Among them, 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 the type of relay protection is determined to be zero-sequence protection, the verification method is determined to be maximum value verification; the operating conditions to be verified include normal operating conditions, transformer tap adjustment operating conditions, single line fault operating conditions, and dual line fault operating conditions, and the relay protection monitoring parameter is zero-sequence current.

[0084] In some embodiments, when the type of relay protection is determined to be differential instantaneous overcurrent protection, the verification method is determined to be minimum value verification; the operating conditions to be verified include maximum operating conditions and minimum operating conditions, and the relay protection monitoring parameters are the currents on each side of the transformer.

[0085] In some embodiments, when the type of relay protection is determined to be the ratio differential protection, the verification method is determined to be the minimum value verification of the current difference; the operating condition to be verified 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 the type of relay protection is determined to be the main transformer overexcitation protection, the verification method is determined to be the maximum value verification; the operating condition to be verified includes the transformer tap adjustment operating 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 a power system, mainly used in power system power flow and stability calculations.

[0088] The maximum operating mode refers to the mode in which the system operates with the maximum power supply capacity and the minimum equivalent impedance, resulting in the maximum short-circuit current in the event of a short circuit. This operating mode is typically used to verify the stability of selected electrical equipment and ensure that the equipment can operate normally under maximum load.

[0089] The minimum operating mode refers to the mode in which the system operates with the minimum power supply capacity and the maximum equivalent impedance, thus minimizing the short-circuit current in the event of a short circuit. This operating mode is mainly used to verify the sensitivity of relay protection devices, ensuring that the relay protection devices can operate correctly under the lowest load.

[0090] Step 20: Under each of the aforementioned operating conditions to be checked, perform the check value determination operation to determine the check value of the relay protection monitoring parameter corresponding to each of the aforementioned operating conditions to be checked.

[0091] In this step, after determining the operating conditions to be checked, it is necessary to determine the check values ​​of the relay protection monitoring parameters under each operating condition to be checked.

[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 operating conditions, single-line fault operating conditions, and double-line fault operating conditions; the relay protection monitoring parameter is zero-sequence current; it is necessary to determine the verification value of zero-sequence current under normal operating conditions, transformer tap adjustment operating conditions, single-line fault operating conditions, and double-line fault operating conditions respectively.

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

[0094] It should be understood that before conducting an abnormal analysis of the relay protection of the three-phase asymmetry of the main transformer in a substation, it is necessary to build a simulation model of the substation in advance, namely an electromagnetic transient analysis model. This electromagnetic transient analysis model is used to simulate the substation, and when verifying the adaptability of various relay protections in the substation, the power flow distribution of this 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 this application include:

[0096] First, the power system topology of the substation is obtained. The power system topology of the substation refers to the connection of the power grid with components such as busbars, generators, synchronous motors, and load points through switching equipment such as circuit breakers, which is abstracted into nodes that are independent of their shape. The power lines connecting these nodes are abstracted into lines, and then the relationship between these nodes is represented in the form of a topology diagram.

[0097] Secondly, the preset modeling parameters of the substation are obtained. These preset modeling parameters include the base capacity, base voltage, per-unit impedance values ​​of each voltage level under the maximum operating mode, equivalent power supply values ​​on the opposite side of each line, and parameters of the three-phase unbalanced transformer. The power system topology of the substation and the preset modeling parameters are stored in the storage unit of the server and can be directly obtained.

[0098] In a specific example, the A phase of the main transformer in a substation is replaced with a standby 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 standby 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 High-medium short-circuit impedance 13.8％ Medium voltage side rated voltage 230kV Short-circuit impedance high-low 37.88％ Low voltage side rated voltage 66kV Short-circuit impedance medium to low 21.56％

[0101] Table 2

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

[0103] Considering the changes in capacity, turns ratio, and short-circuit impedance of the standby transformer compared to the original transformer, the substation was modeled using an electromagnetic transient simulation tool to verify the adaptability of the transformer protection after the replacement of the standby phase, i.e., to analyze whether the relay protection of the substation would malfunction.

[0104] Specifically, system equivalent values ​​were performed on the opposite side of the 14 500kV and 220kV lines of the substation. The impact of unbalanced current on the line and main transformer protection was verified under rated load and rated power operation at maximum operating conditions.

[0105] The base capacity is 1000MVA, and the base voltage is 525kV / 230kV. Under maximum operating conditions, the per-unit impedance values ​​for each voltage level are 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 for each 220kV line are the zero-sequence resistance, zero-sequence reactance, positive sequence resistance, and positive sequence reactance of that 220kV line, which will not be elaborated here.

[0106] Finally, based on the power system topology and the preset modeling parameters, the electromagnetic transient analysis model is constructed, which is used to simulate the substation. That is, a system electromagnetic transient analysis model including the substation's main transformer, busbars, and all substation lines is established based on the actual power system topology and parameters.

[0107] Next, as Figure 2 The following describes the procedure for determining the verification value in this application:

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

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

[0110] Determine the current power flow distribution of the electromagnetic transient analysis model; based on the current power flow distribution and the power flow distribution of the operating condition to be checked, determine the parameters to be adjusted.

[0111] Specifically, determine the current power flow distribution of the electromagnetic transient analysis model, i.e., the current operating condition; based on the current operating condition and the operating condition to be checked, determine the parameters that need to be adjusted, i.e. the parameters to be adjusted.

[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 checked.

[0113] In this step, the power flow distribution in the electromagnetic transient analysis model is adjusted according to the actual power flow of the power system (the power flow distribution of the operating condition to be checked) to make the two as consistent as possible. Specifically, an iterative optimization operation is performed on the parameters to be adjusted to determine the optimal value of the parameters. This 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 checked.

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

[0115] S1. Sequentially determine the simulated values ​​of the target electrical quantities corresponding to the simulated values ​​of each parameter to be adjusted, until it is determined that the Euclidean distance between the simulated value of the target electrical quantity and the theoretical value of the target electrical quantity is less than a preset distance.

[0116] S2. The simulated 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.

[0117] In this application, the simulated values ​​of the target electrical quantities corresponding to the simulated values ​​of each parameter to be adjusted are determined sequentially, and the Euclidean distance between the simulated value and the theoretical value of the target electrical quantity is calculated until it is determined that the Euclidean distance between the simulated value and the theoretical value of the target electrical quantity is less than a preset distance. The simulated value of the target electrical quantity whose Euclidean distance from the theoretical value 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 of the simulation model is made to approximate the given ideal index. When the output deviation stabilizes within a very small range, the identification is considered to be complete. At this point, the simulation control parameters can be regarded as the ideal simulation parameters of the ideal model.

[0119] Adjusting the power flow distribution in the electromagnetic transient analysis model actually involves adjusting the electrical parameters of the model. The main simulation control parameters that need adjustment (i.e., the aforementioned parameters to be adjusted) are the voltage magnitude and phase angle at each node, the active and reactive power of the equivalent power source, and the active and reactive power of the load. The target electrical quantities are the active 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 and formed into an m-dimensional column vector X = [x1, x2, ..., x...]. m ] T The target electrical quantities constitute an n-dimensional column vector Y = [y1, y2, ..., y]. n ] T The ideal values ​​of the target electrical quantities (i.e., the theoretical values ​​of the actual active power and reactive power of each line) constitute the vector Y. z =[y 1z ,y 2z ,...,y nz ] T A threshold ε, i.e., a preset distance, is set. When the Euclidean distance in n-dimensional space between the theoretical value and the process value (i.e., the simulation value) of the target electrical quantity is less than ε during the adjustment of simulation control parameters, the power flow adjustment is considered complete.

[0121]

[0122] At this point, there must be a set of X. z =[x 1z ,x 2z ,...,x mz ]T With Y z Correspondingly, X z These are called ideal simulation parameters, i.e., the optimal values ​​of the parameters to be adjusted. It should be understood that X gradually approaches X0. z The process requires iterative simulation and solution multiple times in the electromagnetic transient analysis model.

[0123] In some optional embodiments of this example, 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. The number of neural units in the input layer is p, where p is the sum of the numbers m and n. The number of neural units in the output layer is m.

[0125] To improve computational efficiency and reduce the number of simulation iterations, a specific algorithm for optimizing ideal simulation parameters can be implemented using a neural network method. This allows the simulation control parameters to approximate the ideal simulation parameters. Neural networks have advantages such as high dimensionality, extensive interconnectivity, and adaptability. As long as the learning samples of the relevant electromagnetic transient analysis model, the initial values ​​of the simulation control parameters, and the target electrical quantities under the corresponding operating conditions (i.e., the operating conditions that need to be actually simulated) are provided, the neural network can learn through autonomous training to obtain the ideal simulation parameters under that operating condition.

[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 nodes. After passing through the action function, the output information of the hidden layer units is transmitted to the output layer units, which then process the signal and provide the output result. If the output layer cannot obtain the expected output, the error of the output signal is returned along the original connection path. By adjusting the weights of the neurons in each layer, the error is minimized (convergence).

[0127] The specific process is as follows: Initial parameters of the neural network are determined, learning samples are input into the neural network, parameter preprocessing is performed, and the neural network is trained to form a neural network simulation parameter knowledge base. When approximating ideal simulation parameters, the initial simulation control parameters and the process values ​​of the target electrical quantities under the corresponding operating conditions (i.e., the initial values ​​of the simulation control parameters and the target electrical quantities under a certain actual operating condition that need to be simulated and calculated) of this simulation model are input into the neural network. Based on the neural network parameter knowledge base, inference calculations are performed to form the ideal simulation parameters under that operating condition. The model of this method is as follows: Figure 4 As 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] The input layer has m+n neural units, which are related to different electromagnetic transient analysis models, specifically consistent with the sum of the simulation control parameters (to be adjusted parameters) and the target electrical quantity in the electromagnetic transient analysis model; the output layer has m neural units, which are related to different electromagnetic transient analysis models, specifically consistent with the number of simulation control parameters in the electromagnetic transient analysis model; the hidden layer has 1 unit; the number of hidden layer neural units can be determined according to the structure of the neural network, and this application does not limit this.

[0131] (2) Determining the input vector. The input vector of the neural network is determined to be an m+n dimensional column vector T = [x1, x2, ..., xn]. m ,y 1z ,y 2z ,...,y nz ] T This refers to the simulation control parameters of the electromagnetic transient analysis model and the target electrical quantities under the corresponding operating conditions. Since the neural network requires the input to be in the interval [0, 1], the input information needs to be normalized.

[0132] (3) Selecting learning samples for neural network learning. Known ideal simulation parameters of electromagnetic transient analysis models under various known operating modes of the substation, as well as target electrical quantities under corresponding operating conditions, are selected as learning samples for neural network learning. 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 error based on the data samples.

[0133] (4) Determine the action function. Neural network algorithms require that the first derivative of the action function of each layer is differentiable everywhere. Usually, the nonlinear Sigmoid function can be selected.

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

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

[0136] Step 203: Based on the optimal value and the electromagnetic transient analysis model, determine the relay protection verification value for the operating condition to be verified.

[0137] In this step, the relay protection verification value for the operating condition to be verified is determined after adjusting 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.

[0138] Step 30: Based on the verification values, the set values ​​of the relay protection monitoring parameters, and the verification method, determine whether there is an abnormality in the relay protection.

[0139] It should be noted that it is necessary to determine the verification values ​​of the relay protection monitoring parameters under all the operating conditions to be verified, so as to determine whether there is any abnormality in the relay protection based on the verification values, the set values ​​of the relay protection monitoring parameters, and the verification method.

[0140] In some optional embodiments of this example, the zero-sequence current protection verification of the line needs to be performed in the following two situations: when a single main transformer is running and when main transformers are running in parallel. In each situation, the verification needs to be carried out under the following operating conditions: under normal conditions, when the transformer tap is adjusted, and when N-1 or N-2 faults occur on each line of the substation. Specifically, when N-1 or N-2 faults occur on each line (double circuit), the corresponding line needs to be disconnected in the electromagnetic transient analysis model, and the power flow distribution of the electromagnetic transient analysis model needs to be adjusted according to the actual power flow. When the transformer tap is adjusted, the voltage values ​​on each side of the transformer also need to be adjusted in the electromagnetic transient analysis model according to the actual tap position of the main transformer on site, and the power transmitted by the model needs to be adjusted according to the actual power flow.

[0141] Each of the above operating conditions requires verification of the zero-sequence current. The purpose is to identify the most stringent operating condition for protection, i.e., the condition with the highest line zero-sequence current. If the zero-sequence current under this condition is still less than the line zero-sequence protection setting value, then the line zero-sequence protection will not malfunction, and the substation's line zero-sequence protection adaptability analysis is deemed to have passed verification and that no abnormalities exist. The line zero-sequence protection adaptability process is as follows: Figure 5 As shown, specifically:

[0142] Begin adaptive analysis; establish an electromagnetic transient analysis model; determine the operating conditions, i.e., the conditions to be checked; optimize simulation parameters and adjust the power flow of the model; determine if the Euclidean distance between Y and Yz is less than ε; if yes, obtain the zero-sequence current in the electromagnetic transient analysis model; if no, continue optimizing simulation parameters and adjusting the power flow of the model; determine if the obtained zero-sequence current is greater than the calculated zero-sequence current; if yes, save the calculation results; if no, discard the calculation results; determine if the operating conditions have been traversed; if no, determine the zero-sequence current of the next operating condition; if yes, determine if the calculation result is less than the protection setting; if yes, pass the zero-sequence protection adaptive analysis; if no, fail the zero-sequence protection adaptive analysis.

[0143] In some embodiments, when the verification method is determined to be the maximum value verification, the maximum value among the verification 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] If the maximum value is less than or equal to the set value, it is determined that the relay protection is not abnormal, i.e., the relay protection adaptability analysis is passed; if the maximum value is greater than the set value, it is determined that the relay protection is abnormal, i.e., the relay protection adaptability analysis is not passed.

[0145] In some embodiments, when the verification method is determined to be the minimum value verification, the minimum value among the verification 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] If the minimum value is greater than or equal to the set value, it is determined that the relay protection is not abnormal, i.e., the relay protection adaptability analysis is passed; if the minimum value is less than the set value, it is determined that the relay protection is abnormal, i.e., the relay protection adaptability analysis is not passed.

[0147] This application verifies 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 in a substation. This effectively prevents protection maloperation, fully guarantees the selectivity of protection, and provides practical support and guarantee for the stable operation of the power grid.

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

[0149] Based on the same inventive concept, this application also provides a relay protection anomaly analysis device for three-phase asymmetry of substation main transformer, which can be used to implement the method described in the above embodiments, as described in the following embodiments. Since the principle of this relay protection anomaly analysis device for three-phase asymmetry of substation main transformer is similar to that of a relay protection anomaly analysis method for three-phase asymmetry of substation main transformer, the implementation of the relay protection anomaly analysis device for three-phase asymmetry of substation main transformer can refer to the implementation of a relay protection anomaly analysis method for three-phase asymmetry of substation main transformer, and repeated details will not be elaborated further. As used below, the terms "unit" or "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the system described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0150] like Figure 6 As shown, this relay protection anomaly analysis device for three-phase asymmetry of substation main transformer includes:

[0151] The first determining module 601 is configured to determine the verification method, relay protection monitoring parameters, and operating conditions to be verified based on the type of relay protection.

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

[0153] The anomaly determination module 603 is configured to determine whether there is an anomaly in the relay protection based on each of the verification values, the set values ​​of the relay protection monitoring parameters, and the verification method.

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

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

[0156] The iterative optimization unit 6022 is configured to 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 checked.

[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 example, such as Figure 8 The diagram also includes a model building module 604, which comprises:

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

[0160] The modeling parameter acquisition unit 6042 is configured to acquire the preset modeling parameters of the substation, wherein the preset modeling parameters include the base capacity, base voltage, per-unit impedance values ​​of each voltage level under the maximum operating mode, the equivalent power supply values ​​of each line opposite side, and the parameters of the three-phase unbalanced transformer.

[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 embodiments of this example, the types of relay protection include zero-sequence protection, differential instantaneous overcurrent protection, ratio differential protection, and main transformer overexcitation protection; the verification methods include maximum value verification and minimum value verification; wherein, as... Figure 9 As shown, the first determining module 601 includes:

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

[0164] The differential instantaneous overcurrent protection determination unit 6012 is configured to determine the verification method as minimum value verification in response to the type of the relay protection being differential instantaneous overcurrent protection; the operating conditions to be verified include the maximum operating mode condition and the minimum operating mode condition, and the relay protection monitoring parameters are the currents on each side of the transformer;

[0165] The ratio differential protection determination unit 6013 is configured to determine the verification method as the minimum value verification of the current difference in response to determining that the type of the relay protection is the ratio differential protection; the operating condition to be verified includes the minimum operating mode 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 such that the type of relay protection is the main transformer overexcitation protection, and 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 embodiments of this example, the verification method includes maximum value verification and minimum value verification, such as... Figure 10 As shown, the anomaly determination module 603 includes:

[0168] The maximum value verification unit 6031 is configured to, in response to determining that the verification method is the maximum value verification, determine the maximum value among the verification values, compare the maximum value with the set value, and determine whether the maximum value is less than or equal to the set value.

[0169] In response to the determination being yes, it is determined that the relay protection is not abnormal;

[0170] If the response is negative, it is determined that the relay protection is malfunctioning.

[0171] Minimum value verification unit 6032 is configured to, in response to determining that the verification method is the minimum value verification, determine the minimum value among the verification values, compare the minimum value with the set value, and determine whether the minimum value is greater than or equal to the set value.

[0172] In response to the determination being yes, it is determined that the relay protection is not abnormal;

[0173] If the response is negative, it is determined that there is an anomaly in the relay protection.

[0174] In some optional embodiments of this example, the parameter determination unit includes:

[0175] The current power flow distribution determination sub-unit is configured to determine the current power flow distribution of the electromagnetic transient analysis model;

[0176] Based on the current power flow distribution and the power flow distribution of the operating condition to be checked, the parameters to be adjusted are determined;

[0177] The parameters to be adjusted include multiple simulation values, and the iterative optimization unit includes:

[0178] The iterative optimization subunit is configured to sequentially determine the simulation value of the target electrical quantity corresponding to the simulation value of each of the parameters 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 simulated 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 embodiments of this example, 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. The number of neural units in the input layer is p, where p is the sum of the numbers m and n. The number of neural units in the output layer is m.

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

[0183] An electronic device includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the steps of a relay protection anomaly analysis method for three-phase asymmetry of a substation main transformer according to the foregoing embodiments.

[0184] A non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to cause a computer to perform the steps of a relay protection anomaly analysis method for three-phase asymmetry of a substation main transformer according to the foregoing embodiments.

[0185] A computer program product includes a computer program / instructions that, when executed by a processor, implement the steps of a relay protection anomaly analysis method for three-phase asymmetry of a substation main transformer according to the foregoing embodiments.

[0186] Figure 11 A schematic block diagram of an example electronic device 900 that can be used to implement embodiments 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 may also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the present disclosure described and / or claimed herein.

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

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

[0189] The computing unit 901 can be a variety of general-purpose and / or special-purpose 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 special-purpose artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. The computing unit 901 performs the various methods and processes described above, such as a method for analyzing relay protection anomalies in three-phase asymmetry of a substation main transformer.

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

[0191] Various embodiments 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-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0192] The program code used to implement the methods of this disclosure may be written in any combination of one or more programming languages. This program code may be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may be executed entirely on a machine, partially on a machine, as a standalone software package partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0193] In the context of this disclosure, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium can be, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, 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), optical storage devices, magnetic storage devices, 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 for displaying information to the user (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor); and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the computer. Other types of devices can also be used to provide interaction with the user; for example, 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 sound input, voice input, or tactile input).

[0195] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as a data server), or computing systems that include middleware components (e.g., an application server), or computing systems that include frontend components (e.g., a user computer with a graphical user interface or web browser through which a user can interact with embodiments of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., a communication network). Examples of communication networks include local area networks (LANs), wide area networks (WANs), and the Internet.

[0196] Computer systems can include clients and servers. Clients and servers are generally located far apart and typically interact via communication networks. Client-server relationships are created by computer programs running on the respective computers and having a client-server relationship with each other. Servers can be cloud servers, servers in distributed systems, or servers incorporating blockchain technology.

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

[0198] The specific embodiments described above do not constitute a limitation on the scope of protection of this disclosure. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A method for analyzing relay protection anomalies in three-phase asymmetry of a substation main transformer, characterized in that, include: Based on the type of relay protection, determine the verification method, relay protection monitoring parameters, and operating conditions to be verified; Under each of the aforementioned operating 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 aforementioned operating conditions to be verified. Based on the verification values, the set values ​​of the relay protection monitoring parameters, and the verification method, it is determined whether there is an abnormality in the relay protection. The verification value determination operation includes: Determine the parameters to be adjusted in the pre-constructed electromagnetic transient analysis model; An iterative optimization operation is performed 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 make the current power flow distribution of the electromagnetic transient analysis model consistent with the power flow distribution of the operating condition to be checked; Based on the optimal value and the electromagnetic transient analysis model, the relay protection verification value for the operating condition to be verified is determined; The verification method includes maximum value verification and minimum value verification. Determining whether the relay protection is abnormal based on each verification value, the set value of the relay protection monitoring parameters, and the verification method includes: In response to determining that the verification method is the maximum value verification, the maximum value among the verification 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; In response to the determination being yes, it is determined that the relay protection is not abnormal; If the response is negative, it is determined that the relay protection is malfunctioning. In response to determining that the verification method is the minimum value verification, the minimum value among the verification 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; In response to the determination being yes, it is determined that the relay protection is not abnormal; If the response is negative, it is determined that there is an anomaly in the relay protection.

2. The relay protection anomaly analysis method according to claim 1, characterized in that, The steps for constructing the electromagnetic transient analysis model include: Obtain the power system topology of the substation; Obtain the preset modeling parameters of the substation, wherein the preset modeling parameters include the base capacity, base voltage, per-unit impedance values ​​of each voltage level under the maximum operating mode, equivalent power supply values ​​on the opposite side of each line, and parameters of the three-phase unbalanced transformer. 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 anomaly analysis method according to claim 1, characterized in that, The types of relay protection include zero-sequence protection, differential instantaneous overcurrent protection, ratio differential protection, and main transformer overexcitation protection. The verification methods include maximum value verification and minimum value verification. Specifically, determining the verification method, relay protection setpoint, and operating condition to be verified based on the type of relay protection includes: In response to determining that the type of the relay protection is the zero-sequence protection, the verification method is determined to be the maximum value verification; the operating conditions to be verified include normal operating conditions, transformer tap adjustment operating conditions, single line fault operating conditions, and dual line fault operating conditions, and the relay protection monitoring parameter is the zero-sequence current.

4. The relay protection anomaly analysis method according to claim 1, characterized in that, The process of determining the parameters to be adjusted in the pre-constructed electromagnetic transient analysis model includes: Determine the current power flow distribution of the electromagnetic transient analysis model; Based on the current power flow distribution and the power flow distribution of the operating condition to be checked, the parameters to be adjusted are determined; The parameters to be adjusted include multiple simulation values, and the iterative optimization operation includes the following steps: The simulated values ​​of the target electrical quantities corresponding to the simulated values ​​of each of the parameters to be adjusted are determined sequentially until the Euclidean distance between the simulated value of the target electrical quantity and the theoretical value of the target electrical quantity is less than a preset distance. The simulated 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.

5. The relay protection anomaly analysis method according to claim 4, 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. The number of neural units in the input layer is p, where p is the sum of the numbers m and n. The number of neural units in the output layer is m.

6. A relay protection anomaly analysis device for three-phase asymmetry of main transformer in a substation, characterized in that, include: The first determining module is configured to determine the verification method, relay protection monitoring parameters, and operating conditions to be verified based on the type of relay protection. The verification value determination module is configured to perform a verification value determination operation under each of the said verification conditions, and determine the verification value of the relay protection monitoring parameter corresponding to each of the said verification conditions; The anomaly determination module is configured to determine whether there is an anomaly in the relay protection based on each of the verification values, the set values ​​of the relay protection monitoring parameters, and the verification method. The verification value determination module includes: The parameter determination unit is configured to determine the parameters to be adjusted in a pre-built electromagnetic transient analysis model; An iterative optimization unit is configured to 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 checked; 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. The verification method includes maximum value verification and minimum value verification, and the anomaly determination module includes: The maximum value verification unit is configured to, in response to determining that the verification method is the maximum value verification, determine the maximum value among the verification values, compare the maximum value with the set value, and determine whether the maximum value is less than or equal to the set value. In response to the determination being yes, it is determined that the relay protection is not abnormal; If the response is negative, it is determined that the relay protection is malfunctioning. A minimum value verification unit is configured to, in response to determining that the verification method is the minimum value verification, determine the minimum value among the verification values, compare the minimum value with the set value, and determine whether the minimum value is greater than or equal to the set value. In response to the determination being yes, it is determined that the relay protection is not abnormal; If the response is negative, it is determined that there is an anomaly in the relay protection.

7. The relay protection anomaly analysis device according to claim 6, characterized in that, It also includes a model building module, which includes: The topology acquisition unit is configured to acquire the power system topology of the substation; The modeling parameter acquisition unit is configured to acquire the preset modeling parameters of the substation, wherein the preset modeling parameters include the base capacity, base voltage, per-unit impedance values ​​of each voltage level under the maximum operating mode, the equivalent power supply values ​​of each line opposite side, and the parameters of the three-phase unbalanced 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.

8. The relay protection anomaly analysis device according to claim 6, characterized in that, The parameter determination unit includes: The current power flow distribution determination sub-unit is configured to determine the current power flow distribution of the electromagnetic transient analysis model; Based on the current power flow distribution and the power flow distribution of the operating condition to be checked, the parameters to be adjusted are determined; The parameters to be adjusted include multiple simulation values, and the iterative optimization unit includes: The iterative optimization subunit is configured to sequentially determine the simulation value of the target electrical quantity corresponding to the simulation value of each of the parameters 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 simulated 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.

9. 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, it implements the steps of the relay protection anomaly analysis method for three-phase asymmetry of the main transformer in a substation as described in any one of claims 1 to 5.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the steps of the relay protection anomaly analysis method for three-phase asymmetry of the main transformer in a substation as described in any one of claims 1 to 5.

11. A computer program product, comprising a computer program / instructions, characterized in that, When the computer program / instruction is executed by the processor, it implements the steps of the relay protection anomaly analysis method for three-phase asymmetry of the main transformer in a substation as described in any one of claims 1 to 5.

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