Relay protection abnormity analysis method and device for access of variable-speed pumped storage unit to power grid

Abstract

The invention provides a relay protection anomaly analysis method and device for access of a variable-speed pumped storage unit to a power grid, and relates to the field of power electronics, and the method comprises the steps: building an electromagnetic transient analysis model based on the access power grid, an access line and a simulation tool of the variable-speed pumped storage unit, and enabling the electromagnetic transient analysis model to be controlled by an AC excitation controller connected to the simulation tool; based on an alternating-current excitation controller and an electromagnetic transient analysis model, line differential protection analysis operation, variable-speed pumping and storage side failure protection analysis operation and bus fault distance first-section protection analysis operation are carried out on a variable-speed pumping and storage unit. Determining a line differential protection analysis result, a variable speed pumping and storage side failure protection analysis result and a bus fault distance section protection analysis result; and determining whether relay protection is abnormal or not based on a line differential protection analysis result, a variable speed pumping and storage side failure protection analysis result and a bus fault distance section protection analysis result.

Description

Technical Field

[0001] The present application belongs to the field of power electronics technology, and in particular to the field of electromechanical protection of generator sets. Specifically, it relates to a method and device for analyzing relay protection anomalies of a variable-speed pumped storage unit connected to a power grid. Background Art

[0002] Pumped-storage power stations support the safe and stable operation of regional power grids, enhance the system's regulation capabilities, quickly track the output of new energy, and play a role in large-capacity energy storage. The variable-speed pumped-storage units have more outstanding performance in terms of operating mode and operating range of water pump conditions, which can enhance the overall regulation capabilities of pumped-storage power stations, effectively improve the system's peak-shaving capabilities, meet part of the peak-shaving demand caused by the rapid growth of regional wind power, ensure the efficient consumption of local new energy, provide favorable conditions for the large-scale development of new energy locally, and inject strong impetus into the high-quality development of the local economy and society.

[0003] Therefore, the construction of variable-speed pumped storage power stations is currently strongly encouraged. The electrical characteristics of variable-speed pumped storage power stations have the characteristics of power electronic devices of converters, and the output of their units will directly affect the amplitude of short-circuit current and fault characteristics and forms, affecting the action results of relay protection. 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 relay protection anomalies when a variable-speed pumped-storage unit is connected to a power grid, analyzing the adaptability of the relay protection after the variable-speed pumped-storage unit is connected to the power system, and preventing the refusal to operate and malfunction of the relay protection device from affecting the power grid.

[0005] According to a first aspect of the present application, a method for analyzing relay protection anomalies of a variable-speed pumped storage unit connected to a power grid is provided, the method comprising:

[0006] Based on the access grid, access line and simulation tool of the variable speed pumped storage unit, an electromagnetic transient analysis model is constructed, wherein the electromagnetic transient analysis model is used to simulate the variable speed pumped storage unit, the access grid and the access line; the electromagnetic transient analysis model is controlled by an AC excitation controller connected to the simulation tool;

[0007] Based on the AC excitation controller and the electromagnetic transient analysis model, the variable speed pumped storage unit is respectively subjected to line differential protection analysis operation, variable speed pumped storage side failure protection analysis operation and busbar fault distance one section protection analysis operation to determine the line differential protection analysis result, variable speed pumped storage side failure protection analysis result and busbar fault distance one section protection analysis result;

[0008] Based on the line differential protection analysis results, the variable speed pumped storage side failure protection analysis results and the busbar fault distance one section protection analysis results, determine whether there is an abnormality in the relay protection.

[0009] In some optional aspects of this embodiment, the line differential protection analysis operation step includes:

[0010] A1. Determine a plurality of working conditions to be verified corresponding to the line differential protection analysis operation;

[0011] A2. Determine the ideal simulation parameters corresponding to the working condition to be verified, wherein the ideal simulation parameters are used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the working condition to be verified;

[0012] A3. Based on the AC excitation controller and the ideal simulation parameters, determine the current line differential protection fault current and the current line differential protection fault voltage of the electromagnetic transient analysis model under the working condition to be verified;

[0013] A4, determine whether the current line differential protection fault current is less than the previous line differential protection fault current and whether the current line differential protection fault voltage is greater than the previous line differential protection fault voltage. If so, determine the current line differential protection fault current and the current line differential protection fault voltage as the line differential protection check value, and execute A5; if not, determine the previous line differential protection fault current and the previous line differential protection fault voltage as the line differential protection check value, and execute A5;

[0014] A5. Determine whether to traverse all the working conditions to be verified. If so, determine the line differential protection analysis result based on the line differential protection setting value and the line differential protection verification value; if not, execute A2 to A4.

[0015] In some optional aspects of this embodiment, the step of analyzing the failure protection operation on the variable speed pumped storage side includes:

[0016] B1. Determine a plurality of working conditions to be verified corresponding to the variable speed pumped storage side failure protection analysis operation;

[0017] B2. Determine the ideal simulation parameters corresponding to the working condition to be verified, wherein the ideal simulation parameters are used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the working condition to be verified;

[0018] B3. Based on the AC excitation controller and the ideal simulation parameters, determine the current variable speed pumped storage side failure protection fault current of the electromagnetic transient analysis model under the working condition to be verified;

[0019] B4, determining whether the current variable speed pumped storage side failure protection fault current is less than the previous variable speed pumped storage side failure protection fault current, if so, determining the current variable speed pumped storage side failure protection fault current as the variable speed pumped storage side failure protection check value, and executing B5; if not, determining the previous variable speed pumped storage side failure protection fault current as the variable speed pumped storage side failure protection check value, and executing B5;

[0020] B5. Determine whether all the working conditions to be verified are traversed. If so, determine the analysis result of the variable speed pumped storage side failure protection based on the variable speed pumped storage side failure protection setting value and the variable speed pumped storage side failure protection verification value; if not, execute B2 to B4.

[0021] In some optional aspects of this embodiment, the steps of the bus fault distance protection analysis operation include:

[0022] C1. Determine a plurality of working conditions to be verified corresponding to the busbar fault distance one-segment protection analysis operation;

[0023] C2. Determine the ideal simulation parameters corresponding to the working condition to be verified, wherein the ideal simulation parameters are used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the working condition to be verified;

[0024] C3. Based on the AC excitation controller and the ideal simulation parameters, determine the current bus fault distance one section protection fault current and the current bus fault distance one section protection fault voltage of the electromagnetic transient analysis model under the working condition to be verified;

[0025] C4, based on the waveform of the current bus fault distance one section protection fault current and the waveform of the current bus fault distance one section protection fault voltage, determine whether the distance protection device is reliable and does not operate under the working condition to be verified, if so, execute C5; if not, determine that the bus fault distance one section protection analysis result is abnormal;

[0026] C5. Determine whether all the working conditions to be checked have been traversed. If so, determine that the analysis result of the bus fault distance one-stage protection is not abnormal; if not, execute steps C2 to C4.

[0027] In some optional aspects of this embodiment, the determining of the ideal simulation parameters corresponding to the working condition to be verified includes:

[0028] Determining simulation parameters to be adjusted and target electrical quantities corresponding to the working condition to be verified, wherein the simulation parameters to be adjusted include multiple simulation values;

[0029] Determining the simulation value of the target electrical quantity corresponding to the simulation value of each simulation parameter to be adjusted in sequence, until it is determined that the cosine similarity between the simulation value of the target electrical quantity and the theoretical value of the target electrical quantity is within a preset similarity interval;

[0030] The simulation value of the simulation parameter to be adjusted corresponding to the simulation value of the target electrical quantity in the preset similarity interval having a cosine similarity with the theoretical value of the target electrical quantity is determined as the ideal simulation parameter.

[0031] In some optional methods of this embodiment, determining whether there is an abnormality in relay protection based on the line differential protection analysis result, the variable speed pumped storage side failure protection analysis result, and the busbar fault distance one section protection analysis result includes:

[0032] Determine whether the line differential protection analysis result, the variable speed pumped storage side failure protection analysis result, and the busbar fault distance protection analysis result are all normal;

[0033] If yes, determine that there is no abnormality in the relay protection; if no, determine that there is an abnormality in the relay protection.

[0034] According to a second aspect of the present application, a relay protection abnormality analysis device for a variable speed pumped storage unit connected to a power grid is also provided, the device comprising:

[0035] The electromagnetic transient analysis model construction module is configured to construct an electromagnetic transient analysis model based on the access grid, access line and simulation tool of the variable speed pumped storage unit, wherein the electromagnetic transient analysis model is used to simulate the variable speed pumped storage unit, the access grid and the access line; the electromagnetic transient analysis model is controlled by an AC excitation controller connected to the simulation tool;

[0036] The relay protection abnormality analysis module is configured to perform line differential protection analysis operations, variable speed pumped storage side failure protection analysis operations and busbar fault distance one section protection analysis operations on the variable speed pumped storage unit based on the AC excitation controller and the electromagnetic transient analysis model, and determine the line differential protection analysis results, the variable speed pumped storage side failure protection analysis results and the busbar fault distance one section protection analysis results;

[0037] The relay protection abnormality determination module is configured to determine whether there is an abnormality in the relay protection based on the line differential protection analysis result, the variable speed pumped storage side failure protection analysis result and the busbar fault distance protection analysis result.

[0038] In some optional aspects of this embodiment, the relay protection abnormality analysis module includes a line differential protection analysis unit, which is configured to perform a line differential protection analysis operation, wherein the steps of the line differential protection analysis operation include:

[0039] A1. Determine a plurality of working conditions to be verified corresponding to the line differential protection analysis operation;

[0040] A2. Determine the ideal simulation parameters corresponding to the working condition to be verified, wherein the ideal simulation parameters are used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the working condition to be verified;

[0041] A3. Based on the AC excitation controller and the ideal simulation parameters, determine the current line differential protection fault current and the current line differential protection fault voltage of the electromagnetic transient analysis model under the working condition to be verified;

[0042] A4, determine whether the current line differential protection fault current is less than the previous line differential protection fault current and whether the current line differential protection fault voltage is greater than the previous line differential protection fault voltage. If so, determine the current line differential protection fault current and the current line differential protection fault voltage as the line differential protection check value, and execute A5; if not, determine the previous line differential protection fault current and the previous line differential protection fault voltage as the line differential protection check value, and execute A5;

[0043] A5. Determine whether to traverse all the working conditions to be verified. If so, determine the line differential protection analysis result based on the line differential protection setting value and the line differential protection verification value; if not, execute A2 to A4.

[0044] In some optional aspects of this embodiment, the relay protection abnormality analysis module includes a variable speed pumped storage side failure protection analysis unit, which is configured to perform a variable speed pumped storage side failure protection analysis operation, wherein the steps of the variable speed pumped storage side failure protection analysis operation include:

[0045] B1. Determine a plurality of working conditions to be verified corresponding to the variable speed pumped storage side failure protection analysis operation;

[0046] B2. Determine the ideal simulation parameters corresponding to the working condition to be verified, wherein the ideal simulation parameters are used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the working condition to be verified;

[0047] B3. Based on the AC excitation controller and the ideal simulation parameters, determine the current variable speed pumped storage side failure protection fault current of the electromagnetic transient analysis model under the working condition to be verified;

[0048] B4, determining whether the current variable speed pumped storage side failure protection fault current is less than the previous variable speed pumped storage side failure protection fault current, if so, determining the current variable speed pumped storage side failure protection fault current as the variable speed pumped storage side failure protection check value, and executing B5; if not, determining the previous variable speed pumped storage side failure protection fault current as the variable speed pumped storage side failure protection check value, and executing B5;

[0049] B5. Determine whether all the working conditions to be verified are traversed. If so, determine the analysis result of the variable speed pumped storage side failure protection based on the variable speed pumped storage side failure protection setting value and the variable speed pumped storage side failure protection verification value; if not, execute B2 to B4.

[0050] In some optional aspects of this embodiment, the relay protection abnormality analysis module includes a bus fault distance one section protection analysis unit, which is configured to perform a bus fault distance one section protection analysis operation, wherein the steps of the bus fault distance one section protection analysis operation include:

[0051] C1. Determine a plurality of working conditions to be verified corresponding to the busbar fault distance one-segment protection analysis operation;

[0052] C2. Determine the ideal simulation parameters corresponding to the working condition to be verified, wherein the ideal simulation parameters are used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the working condition to be verified;

[0053] C3. Based on the AC excitation controller and the ideal simulation parameters, determine the current bus fault distance one section protection fault current and the current bus fault distance one section protection fault voltage of the electromagnetic transient analysis model under the working condition to be verified;

[0054] C4, based on the waveform of the current bus fault distance one section protection fault current and the waveform of the current bus fault distance one section protection fault voltage, determine whether the distance protection device is reliable and does not operate under the working condition to be verified, if so, execute C5; if not, determine that the bus fault distance one section protection analysis result is abnormal;

[0055] C5. Determine whether all the working conditions to be checked have been traversed. If so, determine that the analysis result of the bus fault distance one-stage protection is not abnormal; if not, execute steps C2 to C4.

[0056] 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 relay protection anomalies of a variable-speed pumped storage unit connected to a power grid are implemented.

[0057] 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 relay protection abnormality analysis method for a variable-speed pumped storage unit connected to a power grid are implemented.

[0058] According to the fifth aspect of the present application, there is also provided a computer program product, comprising a computer program / instruction, which, when executed by a processor, implements the steps of the aforementioned method for analyzing relay protection anomalies of a variable-speed pumped storage unit connected to a power grid.

[0059] The present application provides a method and device for analyzing relay protection anomalies when a variable-speed pumped-storage unit is connected to a power grid. After the variable-speed pumped-storage unit is connected to the power grid, adaptive analysis of related relay protection can effectively prevent refusal to operate and malfunction of line protection, 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

[0060] 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.

[0061] Figure 1 It is a flow chart of a relay protection abnormality analysis method for a variable speed pumped storage unit connected to a power grid according to an embodiment of the present application;

[0062] Figure 2 A hardware-in-the-loop principle diagram of a variable-speed pumped storage unit according to an embodiment of the present application;

[0063] Figure 3 is a flow chart of a line differential protection analysis operation according to an embodiment of the present application;

[0064] Figure 4 It is a flow chart of the variable speed pumped storage side failure protection analysis operation according to an embodiment of the present application;

[0065] Figure 5 A flowchart of a busbar fault distance protection analysis operation according to an embodiment of the present application;

[0066] Figure 6 is a protection adaptability analysis flow chart according to an embodiment of the present application;

[0067] Figure 7 is a schematic diagram of a model reference adaptive identification method according to an embodiment of the present application;

[0068] Figure 8Schematic diagram of a process for determining ideal simulation parameters of an electromagnetic transient model based on a genetic algorithm according to an embodiment of the present application;

[0069] Fig. 9 It is a structural diagram of a relay protection abnormality analysis device for a variable speed pumped storage unit connected to a power grid according to an embodiment of the present application;

[0070] Fig.10 Schematic diagram of the structure of the relay protection abnormality analysis module according to an embodiment of the present application;

[0071] Fig.11 A block diagram of an electronic device used to implement an embodiment of the present application. DETAILED DESCRIPTION

[0072] 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.

[0073] The electrical characteristics of the variable-speed pumped-storage power station have the characteristics of power electronic devices of the converter. The output of its unit will directly affect the amplitude of the short-circuit current, the fault characteristics and form, and the action result of the relay protection. It is necessary to adjust its power flow and carry out electromagnetic transient adaptability analysis, and conduct adaptability analysis of the relevant relay protection after the variable-speed pumped-storage unit is connected to the power grid, that is, relay protection abnormality analysis.

[0074] In view of this, an embodiment of the present application provides a method for analyzing relay protection anomalies when a variable speed pumped storage unit is connected to a power grid, such as Figure 1 As shown, the method includes:

[0075] Step 10: Based on the access grid, access line and simulation tool of the variable speed pumped storage unit, an electromagnetic transient analysis model is constructed, wherein the electromagnetic transient analysis model is used to simulate the variable speed pumped storage unit, the access grid and the access line; the electromagnetic transient analysis model is controlled by an AC excitation controller connected to the simulation tool.

[0076] In this application, according to the grid structure of the variable-speed pumped-storage power station connected to the power grid, an electromagnetic transient simulation model containing the power grid and related lines and the variable-speed pumped-storage unit is built based on a real-time digital simulation tool. The AC excitation controller of the variable-speed pumped-storage unit is connected to the simulation tool through an external board of the real-time digital simulation tool. Through the measured parameters of the actual power grid and equipment, the operating characteristics of the actual power grid and unit can be more realistically reflected. This method can be called: variable-speed pumped-storage unit AC excitation controller hardware-in-the-loop.

[0077] (1) Principle of hardware-in-the-loop test

[0078] The experiment is based on real-time digital simulation tools to establish power grid and unit models related to variable-speed pumped storage units, including simulation environments of doubly-fed motors, converters, box transformers, main switches and equivalent infinite power supplies. The required rotor current, rotor voltage, DC bus voltage, grid voltage, grid-connected current, stator current, stator voltage, speed encoder and other analog and digital signals are provided to the AC excitation controller equipment. The switch pulse signal, Chopper and main switch action signal output by the AC excitation controller are input into the real-time digital simulation tool. The rotor voltage of the doubly-fed motor is obtained through the AC excitation converter model, forming a structure such as Figure 2 The hardware-in-the-loop platform of the AC excitation controller is shown.

[0079] (2) AC excitation controller hardware-in-the-loop platform

[0080] The primary system of the variable-speed pumped-storage unit in the pumped-storage power station is built based on real-time simulation tools. The relevant signals are connected to the AC excitation control device through the IO board interface device to interact with the AC excitation control device, forming a hardware-in-the-loop platform for the variable-speed pumped-storage AC excitation controller to simulate the topological architecture of the variable-speed pumped-storage power station and the nearby power grid.

[0081] So far, in this embodiment, based on the access grid, access line and simulation tool of the variable speed pumped storage unit, an electromagnetic transient analysis model for simulating the variable speed pumped storage unit, the access grid and the access line can be constructed, and the electromagnetic transient analysis model is controlled by the AC excitation controller connected to the simulation tool.

[0082] Step 20: Based on the AC excitation controller and the electromagnetic transient analysis model, the variable speed pumped storage unit is subjected to line differential protection analysis, variable speed pumped storage side failure protection analysis, and busbar fault distance one section protection analysis to determine the line differential protection analysis results, variable speed pumped storage side failure protection analysis results, and busbar fault distance one section protection analysis results.

[0083] It should be noted that line differential protection is a protection device that detects and removes faults by comparing the magnitude and phase of the current at both ends of the line. It uses the current difference at both ends of the line as the basis for action judgment. When the difference exceeds the predetermined threshold, the protection device will start to remove the fault. Among them, when the line is operating normally, the current at both ends is equal in magnitude and opposite in phase, and the difference is zero; when a line fault occurs, the current magnitude and phase at both ends of the fault point change, and the difference is not zero; the differential protection device determines the location and type of the fault based on the magnitude and direction of the difference, and takes corresponding action measures.

[0084] Failure protection on the variable speed pumped storage side is an important protection method in the power system. Its main function is to remove the fault through the failure protection device when a circuit breaker in the system cannot be disconnected normally for some reason, prevent the fault from expanding, and ensure the stable operation of the power system. The action conditions of failure protection are mainly: when the circuit breaker refuses to operate, the failure protection device will detect the fault current and delay the start. If the fault still exists after the delay, a trip command will be issued to trip all circuit breakers related to the circuit breaker.

[0085] Power system distance protection is a commonly used protection method in power systems, which can protect power equipment such as transmission lines and substations. Distance protection is usually divided into three sections (i.e., one section, two sections, and three sections), and each section has a different protection range and function; the range is usually from the fault point to the nearest endpoint (such as a transformer, generator set, or one or both ends of a line winding, one end of a busbar), and differential protection is usually used to detect faults in the power system by measuring the difference in current at both ends of the power equipment. When the differential current exceeds a certain threshold, the protection device will send a signal to the circuit breaker to cut off the power supply to the corresponding part of the power system to prevent power equipment from being damaged due to the fault.

[0086] Specifically, the first protection range of distance protection can be divided into the following parts: for transformers, the first protection range of distance protection is the area between the high-voltage and low-voltage windings of the transformer; for generator sets, the first protection range of distance protection is the area where the generator windings are located; Lines: For transmission lines, the first protection range of distance protection is one or both ends of the line windings; for busbars, the first protection range of distance protection is one or both ends of the busbars.

[0087] In some optional embodiments of this embodiment, Figure 3 As shown, the steps of the line differential protection analysis operation include:

[0088] A1. Determine a plurality of working conditions to be verified corresponding to the line differential protection analysis operation;

[0089] A2. Determine the ideal simulation parameters corresponding to the working condition to be verified, wherein the ideal simulation parameters are used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the working condition to be verified;

[0090] A3. Based on the AC excitation controller and the ideal simulation parameters, determine the current line differential protection fault current and the current line differential protection fault voltage of the electromagnetic transient analysis model under the working condition to be verified;

[0091] A4, determine whether the current line differential protection fault current is less than the previous line differential protection fault current and whether the current line differential protection fault voltage is greater than the previous line differential protection fault voltage. If so, determine the current line differential protection fault current and the current line differential protection fault voltage as the line differential protection check value (step A41), and execute A5; if not, determine the previous line differential protection fault current and the previous line differential protection fault voltage as the line differential protection check value (step A42), and execute A5;

[0092] A5. Determine whether all the working conditions to be verified have been traversed. If so, determine the line differential protection analysis result based on the line differential protection setting value and the line differential protection verification value (step A51); if not, execute A2 to A4.

[0093] In a specific example, the line differential protection start value is checked as follows:

[0094] Check whether the differential protection of the line can be started normally when four types of faults (single-phase grounding, two-phase grounding, two-phase short circuit, three-phase short circuit) occur at the head and end of the power station transmission line when the system is in the normal operation mode (no line maintenance) under the minimum operation mode of the variable-speed pumped-storage power station.

[0095] According to the actual operation flow of the power system, the flow distribution in the model is adjusted to keep the two as consistent as possible. The fault current and voltage on both sides of the line are obtained and compared with the line differential protection start value to determine whether the start conditions are met.

[0096] Each of the above fault conditions requires the verification of the fault current and voltage, with the goal of finding the most demanding condition for protection, that is, the condition with the smallest fault current and the highest voltage on one side of the line. When the current and voltage under this condition meet the starting conditions, it is determined that the line differential protection starting value has passed the verification.

[0097] In some optional embodiments of this embodiment, Figure 4 As shown, the steps of the variable speed pumped storage side failure protection analysis operation include:

[0098] B1. Determine a plurality of working conditions to be verified corresponding to the variable speed pumped storage side failure protection analysis operation;

[0099] B2. Determine the ideal simulation parameters corresponding to the working condition to be verified, wherein the ideal simulation parameters are used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the working condition to be verified;

[0100] B3. Based on the AC excitation controller and the ideal simulation parameters, determine the current variable speed pumped storage side failure protection fault current of the electromagnetic transient analysis model under the working condition to be verified;

[0101] B4, determining whether the current variable speed pumped storage side failure protection fault current is less than the previous variable speed pumped storage side failure protection fault current, if so, determining the current variable speed pumped storage side failure protection fault current as the variable speed pumped storage side failure protection check value (step B41), and executing B5; if not, determining the previous variable speed pumped storage side failure protection fault current as the variable speed pumped storage side failure protection check value (step B42), and executing B5;

[0102] B5. Determine whether all the working conditions to be verified have been traversed. If so, determine the analysis result of the variable speed pumped storage side failure protection based on the variable speed pumped storage side failure protection setting value and the variable speed pumped storage side failure protection verification value (step B51); if not, execute B2 to B4.

[0103] In a specific example, the failure protection check of the variable speed pumped storage side is as follows:

[0104] Check whether the circuit breaker failure protection on the line side can be activated when the switch on the opposite side of the line trips when the variable speed pumped storage unit is operating alone on a single line and four types of faults occur on the opposite side of its transmission line (single-phase grounding, two-phase grounding, two-phase short circuit, three-phase short circuit).

[0105] According to the actual operation flow of the power system, the flow distribution in the model is adjusted to keep the two as consistent as possible. The fault current on the line side is obtained and compared with the action value of the failure protection to determine whether the action conditions of the failure protection are met.

[0106] Each of the above fault conditions requires the fault current to be checked in order to find the most demanding condition for protection, that is, the condition with the smallest fault current on the line side. When the current under this condition meets the action conditions, the line failure protection is determined to have passed the verification.

[0107] In some optional embodiments of this embodiment, Figure 5 As shown, the steps of the bus fault distance protection analysis operation include:

[0108] C1. Determine a plurality of working conditions to be verified corresponding to the busbar fault distance one-segment protection analysis operation;

[0109] C2. Determine the ideal simulation parameters corresponding to the working condition to be verified, wherein the ideal simulation parameters are used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the working condition to be verified;

[0110] C3. Based on the AC excitation controller and the ideal simulation parameters, determine the current bus fault distance one section protection fault current and the current bus fault distance one section protection fault voltage of the electromagnetic transient analysis model under the working condition to be verified;

[0111] C4, based on the waveform of the current bus fault distance one section protection fault current and the waveform of the current bus fault distance one section protection fault voltage, determine whether the distance protection device is reliable and does not operate under the working condition to be verified, if so, execute C5; if not, determine that the bus fault distance one section protection analysis result is abnormal (step C41);

[0112] C5. Determine whether all the working conditions to be checked have been traversed. If so, determine that the bus fault distance protection analysis result is not abnormal (step C51); if not, execute steps C2 to C4.

[0113] In a specific example, the protection check of the busbar fault distance on both sides of the line is as follows:

[0114] Check whether the line distance protection can be reliably not operated when the variable speed pumped storage power station is in the minimum operating mode and the system is in normal operating mode (no line maintenance) and four types of faults occur on the substation busbars on both sides of its transmission line (single-phase grounding, two-phase grounding, two-phase short circuit, three-phase short circuit).

[0115] Adjust the power flow distribution in the model according to the actual power system operation power flow to keep the two as consistent as possible. Obtain the comtrade format file of the fault voltage and current waveforms on both sides of the line and play them back on the corresponding distance protection device to confirm that it is reliable and does not operate.

[0116] In some optional aspects of this embodiment, the determining of the ideal simulation parameters corresponding to the working condition to be verified includes:

[0117] Determining simulation parameters to be adjusted and target electrical quantities corresponding to the working condition to be verified, wherein the simulation parameters to be adjusted include multiple simulation values;

[0118] Determining the simulation value of the target electrical quantity corresponding to the simulation value of each simulation parameter to be adjusted in sequence, until it is determined that the cosine similarity between the simulation value of the target electrical quantity and the theoretical value of the target electrical quantity is within a preset similarity interval;

[0119] The simulation value of the simulation parameter to be adjusted corresponding to the simulation value of the target electrical quantity in the preset similarity interval having a cosine similarity with the theoretical value of the target electrical quantity is determined as the ideal simulation parameter.

[0120] Specifically, the protection adaptability analysis process is as follows: Figure 6 In the above steps, the specific method of making the power flow distribution in the electromagnetic transient model gradually approach the actual power flow of the power system is shown in the optimization part of the electromagnetic transient model simulation parameters below. Figure 6 , specifically:

[0121] Start adaptive 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 cosine similarity of Y and Yz is close to 1; if so, obtain the target electrical quantity in the model; if not, continue to optimize simulation parameters and adjust the model operating flow; determine whether the protection is more stringent than the previous condition based on the obtained target electrical quantity (for example, determine whether the current line differential protection fault current is less than the previous line differential protection fault current and whether the current line differential protection fault voltage is greater than the previous line differential protection fault voltage), if so, save the calculation result; if not, abandon the calculation result; determine whether the operating condition has been traversed, if not, perform simulation optimization for the next operating condition; if so, compare the calculation result with the relevant protection setting to determine whether the adaptive analysis has passed.

[0122] The optimization of simulation parameters in the electromagnetic transient model uses the model reference adaptive MRAS (Model Reference Adaptive System) identification method. Figure 7 By adjusting the simulation parameters, the output results of the simulation model are close to the given ideal index. When the output deviation is stable within a very small range, the identification is considered to be completed. At this time, the simulation parameters can be regarded as the control parameters of the ideal model.

[0123] When adjusting the power flow distribution in the electromagnetic transient model, it is actually necessary to adjust the parameters of each electrical quantity in the model. The main simulation parameters that need to be adjusted (i.e., the simulation parameters to be adjusted corresponding to the aforementioned working conditions to be verified) 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., and the target electrical quantity to be adjusted is the active power and reactive power of each line. Figure 7 The ideal performance index in is the theoretical value of the target electrical quantity, which can also be called the ideal value of the target electrical quantity.

[0124] The simulation parameters that need to be adjusted are extracted from the electromagnetic transient 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 . Set the threshold ε, when in the process of simulation parameter adjustment, the ideal value vector Y of the target electrical quantity zWhen the difference between the cosine similarity between the process value (i.e., simulation value) vector Y in the n-dimensional space and 1 is less than ε (i.e., the cosine similarity approaches 1), it is considered that the operation flow adjustment is complete, that is, formula (1) is satisfied:

[0125] |(Y·Y z ) / (||Y|| ||Y z ||) -1|<ε (1)

[0126] where “·” represents the dot product, ||Y|| and ||Y z || represents vectors Y and Y respectively z The mold length.

[0127] When the above conditions are met, there must be a set of X z =[x 1z ,x 2z ,...,x mz ] T With Y z Correspondingly, X z It is called the ideal simulation parameter. It should be understood that X gradually approaches X z The process requires multiple iterations of simulation to solve the electromagnetic transient analysis model.

[0128] In order to improve the computational efficiency and reduce the number of simulation iterations, the specific ideal simulation parameter optimization algorithm can use a genetic algorithm to make the simulation parameters to be adjusted close to the ideal simulation parameters. Genetic algorithm is a method of searching for the optimal solution by simulating the natural evolution process, which converts the problem-solving process into a process similar to the replication and mutation of chromosome genes in biological evolution. By providing the initial values ​​of the simulation parameters to be adjusted of the relevant electromagnetic transient analysis model, the genetic algorithm can obtain the ideal simulation parameters under the working condition to be verified through autonomous calculation.

[0129] The m-dimensional column vector X=[x1,x2,...,x m ] T As the chromosome of the genetic algorithm, each element x1, x2, ..., x m All of them are used as genes in a genetic algorithm.

[0130] The genetic algorithm will perform multiple iterations during operation, and each iteration will generate several chromosomes (i.e., simulation parameters to be adjusted). The fitness function is set here to score each chromosome to judge the fitness of these simulation parameters. For a column vector X composed of a simulation parameter to be adjusted, the corresponding target electrical quantity constitutes an n-dimensional column vector Y. The idea of ​​setting the fitness function is: when Y and Y z The cosine similarity S = (Y·Y z) / (||Y||||Y z The higher the ||), the higher the score value. Therefore, the fitness function of the genetic algorithm is:

[0131]

[0132] Genetic algorithm selection is to select some chromosomes to generate the next generation. Among them, a commonly used selection strategy is proportional selection, that is, the probability of an individual being selected is proportional to the value of its fitness function. This application adopts the following method: for chromosomes with S≥0.9, all are selected to enter the next generation; for chromosomes with 0.8 < S < 0.9, 50% of their quantity is randomly selected to enter the next generation, and the rest are discarded; for chromosomes with S≤0.8, they are discarded.

[0133] Genetic algorithm mutation is to replace some gene values in the individual coding string with other gene values according to the mutation probability, so as to form a new individual. Mutation operation is an auxiliary method for generating new individuals. It determines the local search ability of the algorithm and maintains the diversity of chromosomes. To make up for the number of discarded chromosomes in the next generation iteration, the discarded chromosomes in this generation can enter the next generation through the mutation of some genes. Here, some genes of the discarded chromosomes can be appropriately increased or decreased according to the mutation probability and mutated into new chromosomes to enter the next generation. The smaller the corresponding S value of the chromosome, the greater its mutation probability. The stopping condition of this genetic algorithm is the same as formula (1). The calculation model of this genetic algorithm is as Figure 8 shown.

[0134] First, determine the chromosome set of the electromagnetic transient analysis model; second, determine the initial chromosome (i.e., population initialization); second, select chromosomes based on fitness, perform replication and gene mutation of chromosomes, and generate the next generation of chromosomes; judge whether the stopping condition is met. If so, output the optimal chromosome (obtain the ideal simulation parameters); if not, add 1 to the number of iterations, and start repeating from "select chromosomes based on fitness" until the stopping condition is met.

[0135] Step 30: Determine whether there is an abnormality in the relay protection based on the line differential protection analysis result, the loss-of-function protection analysis result on the variable-speed pumped storage side, and the first-segment protection analysis result of the bus fault distance.

[0136] In some alternative ways of this embodiment, the determining whether there is an abnormality in the relay protection based on the line differential protection analysis result, the loss-of-function protection analysis result on the variable-speed pumped storage side, and the first-segment protection analysis result of the bus fault distance includes:

[0137] Determine whether the line differential protection analysis results, the variable speed pumped storage side failure protection analysis results and the busbar fault distance protection analysis results are all normal; if so, determine that there is no abnormality in the relay protection; if not, determine that there is an abnormality in the relay protection.

[0138] So far, the above scheme is summarized. In this application:

[0139] After the variable speed pumped storage unit is connected to the power grid, the analysis steps and contents for the adaptability of related protections include model establishment and relay protection verification. In the model establishment, the simulation platform is established by adopting the hardware-in-the-loop method of the AC excitation controller of the variable speed pumped storage unit mentioned above; in the relay protection verification, the first is the line differential protection start value verification; the second is the variable speed pumped storage side failure protection verification; the third is the busbar fault distance protection verification on both sides of the line; and the working condition selection during the verification process of each type of protection.

[0140] In the model reference adaptive identification method for optimizing simulation parameters in electromagnetic transient models, cosine similarity is used to characterize the closeness of two vectors, and it is set as the condition for successful identification of simulation parameters. The specific "ideal simulation parameter" optimization algorithm can use a genetic algorithm to make the simulation parameters to be adjusted close to the ideal simulation parameters, including the selection of chromosomes, the construction of fitness functions, mutation methods and stop conditions.

[0141] Based on a relay protection anomaly analysis method for a variable-speed pumped-storage unit connected to a power grid in this embodiment, after the variable-speed pumped-storage unit is connected to the power grid, adaptive analysis of relevant relay protection can effectively prevent refusal to operate and malfunction of line protection, fully ensure the selectivity of protection, and provide practical support and guarantee for the stable operation of the power grid.

[0142] Based on the same inventive concept, the embodiment of the present application also provides a relay protection abnormality analysis device for a variable speed pumped storage unit connected to a power grid, 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 relay protection abnormality analysis device for a variable speed pumped storage unit connected to a power grid is similar to that of a relay protection abnormality analysis method for a variable speed pumped storage unit connected to a power grid, the implementation of a relay protection abnormality analysis device for a variable speed pumped storage unit connected to a power grid can refer to the implementation of a relay protection abnormality analysis method for a variable speed pumped storage unit connected to a power grid, and the repetitions will not be repeated. As used below, the term "unit" or "module" can be a combination of software and / or hardware that implements 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.

[0143] like Fig. 9 As shown, the relay protection abnormality analysis device for a variable speed pumped storage unit connected to a power grid comprises:

[0144] The electromagnetic transient analysis model construction module 601 is configured to construct an electromagnetic transient analysis model based on the access grid, access line and simulation tool of the variable speed pumped storage unit, wherein the electromagnetic transient analysis model is used to simulate the variable speed pumped storage unit, the access grid and the access line; the electromagnetic transient analysis model is controlled by an AC excitation controller connected to the simulation tool;

[0145] The relay protection abnormality analysis module 602 is configured to perform line differential protection analysis operations, variable speed pumped storage side failure protection analysis operations and busbar fault distance one section protection analysis operations on the variable speed pumped storage unit based on the AC excitation controller and the electromagnetic transient analysis model, and determine the line differential protection analysis results, the variable speed pumped storage side failure protection analysis results and the busbar fault distance one section protection analysis results;

[0146] The relay protection abnormality determination module 603 is configured to determine whether there is an abnormality in the relay protection based on the line differential protection analysis result, the variable speed pumped storage side failure protection analysis result and the busbar fault distance protection analysis result.

[0147] In some optional embodiments of this embodiment, Fig.10 As shown, the relay protection abnormality analysis module includes a line differential protection analysis unit 6021, which is configured to perform a line differential protection analysis operation, wherein the steps of the line differential protection analysis operation include:

[0148] A1. Determine a plurality of working conditions to be verified corresponding to the line differential protection analysis operation;

[0149] A2. Determine the ideal simulation parameters corresponding to the working condition to be verified, wherein the ideal simulation parameters are used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the working condition to be verified;

[0150] A3. Based on the AC excitation controller and the ideal simulation parameters, determine the current line differential protection fault current and the current line differential protection fault voltage of the electromagnetic transient analysis model under the working condition to be verified;

[0151] A4, determine whether the current line differential protection fault current is less than the previous line differential protection fault current and whether the current line differential protection fault voltage is greater than the previous line differential protection fault voltage. If so, determine the current line differential protection fault current and the current line differential protection fault voltage as the line differential protection check value, and execute A5; if not, determine the previous line differential protection fault current and the previous line differential protection fault voltage as the line differential protection check value, and execute A5;

[0152] A5. Determine whether to traverse all the working conditions to be verified. If so, determine the line differential protection analysis result based on the line differential protection setting value and the line differential protection verification value; if not, execute A2 to A4.

[0153] In some optional embodiments of this embodiment, Fig.10 As shown, the relay protection abnormality analysis module includes a variable speed pumped storage side failure protection analysis unit 6022, which is configured to perform a variable speed pumped storage side failure protection analysis operation, wherein the steps of the variable speed pumped storage side failure protection analysis operation include:

[0154] B1. Determine a plurality of working conditions to be verified corresponding to the variable speed pumped storage side failure protection analysis operation;

[0155] B2. Determine the ideal simulation parameters corresponding to the working condition to be verified, wherein the ideal simulation parameters are used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the working condition to be verified;

[0156] B3. Based on the AC excitation controller and the ideal simulation parameters, determine the current variable speed pumped storage side failure protection fault current of the electromagnetic transient analysis model under the working condition to be verified;

[0157] B4, determining whether the current variable speed pumped storage side failure protection fault current is less than the previous variable speed pumped storage side failure protection fault current, if so, determining the current variable speed pumped storage side failure protection fault current as the variable speed pumped storage side failure protection check value, and executing B5; if not, determining the previous variable speed pumped storage side failure protection fault current as the variable speed pumped storage side failure protection check value, and executing B5;

[0158] B5. Determine whether all the working conditions to be verified are traversed. If so, determine the analysis result of the variable speed pumped storage side failure protection based on the variable speed pumped storage side failure protection setting value and the variable speed pumped storage side failure protection verification value; if not, execute B2 to B4.

[0159] In some optional embodiments of this embodiment, Fig.10 As shown, the relay protection abnormality analysis module includes a bus fault distance one section protection analysis unit 6023, which is configured to perform a bus fault distance one section protection analysis operation, wherein the steps of the bus fault distance one section protection analysis operation include:

[0160] C1. Determine a plurality of working conditions to be verified corresponding to the busbar fault distance one-segment protection analysis operation;

[0161] C2. Determine the ideal simulation parameters corresponding to the working condition to be verified, wherein the ideal simulation parameters are used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the working condition to be verified;

[0162] C3. Based on the AC excitation controller and the ideal simulation parameters, determine the current bus fault distance one section protection fault current and the current bus fault distance one section protection fault voltage of the electromagnetic transient analysis model under the working condition to be verified;

[0163] C4, based on the waveform of the current bus fault distance one section protection fault current and the waveform of the current bus fault distance one section protection fault voltage, determine whether the distance protection device is reliable and does not operate under the working condition to be verified, if so, execute C5; if not, determine that the bus fault distance one section protection analysis result is abnormal;

[0164] C5. Determine whether all the working conditions to be checked have been traversed. If so, determine that the bus fault distance one-stage protection analysis result is not abnormal; if not, execute steps C2 to C4.

[0165] 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.

[0166] 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 relay protection abnormality analysis method for a variable speed pumped storage unit connected to a power grid in the aforementioned embodiment.

[0167] 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 relay protection anomaly analysis method for a variable-speed pumped storage unit connected to a power grid in the aforementioned embodiment.

[0168] A computer program product includes a computer program / instruction, which, when executed by a processor, implements the steps of a relay protection anomaly analysis method for a variable-speed pumped storage unit connected to a power grid in the aforementioned embodiment.

[0169] 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.

[0170] 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.

[0171] 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.

[0172] 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 relay protection abnormality analysis method for a variable speed pumped storage unit connected to a power grid.

[0173] For example, in some embodiments, a method for analyzing anomalies of relay protection of a variable speed pumped storage unit connected to a power grid 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 anomalies of relay protection of a variable speed pumped storage unit connected to a power grid described above can be executed. Alternatively, in other embodiments, the computing unit 901 can be configured to execute a method for analyzing anomalies of relay protection of a variable speed pumped storage unit connected to a power grid by any other appropriate means (e.g., by means of firmware).

[0174] 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.

[0175] 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, enables the functions / operations specified in the flow chart and / or block diagram to be implemented. 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.

[0176] 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.

[0177] 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).

[0178] 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.

[0179] 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.

[0180] 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.

[0181] 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 relay protection anomalies when a variable speed pumped storage unit is connected to a power grid, characterized in that: include: Based on the access grid, access line and simulation tool of the variable speed pumped storage unit, an electromagnetic transient analysis model is constructed, wherein the electromagnetic transient analysis model is used to simulate the variable speed pumped storage unit, the access grid and the access line; the electromagnetic transient analysis model is controlled by an AC excitation controller connected to the simulation tool; Based on the AC excitation controller and the electromagnetic transient analysis model, the variable speed pumped storage unit is respectively subjected to line differential protection analysis operation, variable speed pumped storage side failure protection analysis operation and busbar fault distance one section protection analysis operation to determine the line differential protection analysis result, variable speed pumped storage side failure protection analysis result and busbar fault distance one section protection analysis result; Based on the line differential protection analysis results, the variable speed pumped storage side failure protection analysis results and the busbar fault distance one section protection analysis results, determine whether there is an abnormality in the relay protection.

2. The relay protection abnormality analysis method according to claim 1, characterized in that: The steps of the line differential protection analysis operation include: A1. Determine a plurality of working conditions to be verified corresponding to the line differential protection analysis operation; A2. Determine the ideal simulation parameters corresponding to the working condition to be verified, wherein the ideal simulation parameters are used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the working condition to be verified; A3. Based on the AC excitation controller and the ideal simulation parameters, determine the current line differential protection fault current and the current line differential protection fault voltage of the electromagnetic transient analysis model under the working condition to be verified; A4, determine whether the current line differential protection fault current is less than the previous line differential protection fault current and whether the current line differential protection fault voltage is greater than the previous line differential protection fault voltage. If so, determine the current line differential protection fault current and the current line differential protection fault voltage as the line differential protection check value, and execute A5; if not, determine the previous line differential protection fault current and the previous line differential protection fault voltage as the line differential protection check value, and execute A5; A5. Determine whether to traverse all the working conditions to be verified. If so, determine the line differential protection analysis result based on the line differential protection setting value and the line differential protection verification value; if not, execute A2 to A4.

3. The relay protection abnormality analysis method according to claim 1, characterized in that: The steps of analyzing and operating the failure protection of the variable speed pumped storage side include: B1. Determine a plurality of working conditions to be verified corresponding to the variable speed pumped storage side failure protection analysis operation; B2. Determine the ideal simulation parameters corresponding to the working condition to be verified, wherein the ideal simulation parameters are used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the working condition to be verified; B3. Based on the AC excitation controller and the ideal simulation parameters, determine the current variable speed pumped storage side failure protection fault current of the electromagnetic transient analysis model under the working condition to be verified; B4, determining whether the current variable speed pumped storage side failure protection fault current is less than the previous variable speed pumped storage side failure protection fault current, if so, determining the current variable speed pumped storage side failure protection fault current as the variable speed pumped storage side failure protection check value, and executing B5; if not, determining the previous variable speed pumped storage side failure protection fault current as the variable speed pumped storage side failure protection check value, and executing B5; B5. Determine whether all the working conditions to be verified are traversed. If so, determine the analysis result of the variable speed pumped storage side failure protection based on the variable speed pumped storage side failure protection setting value and the variable speed pumped storage side failure protection verification value; if not, execute B2 to B4.

4. The relay protection abnormality analysis method according to claim 1, characterized in that: The steps of the busbar fault distance protection analysis operation include: C1. Determine a plurality of working conditions to be verified corresponding to the busbar fault distance one-segment protection analysis operation; C2. Determine the ideal simulation parameters corresponding to the working condition to be verified, wherein the ideal simulation parameters are used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the working condition to be verified; C3. Based on the AC excitation controller and the ideal simulation parameters, determine the current bus fault distance one section protection fault current and the current bus fault distance one section protection fault voltage of the electromagnetic transient analysis model under the working condition to be verified; C4, based on the waveform of the current bus fault distance one section protection fault current and the waveform of the current bus fault distance one section protection fault voltage, determine whether the distance protection device is reliable and does not operate under the working condition to be verified, if so, execute C5; if not, determine that the bus fault distance one section protection analysis result is abnormal; C5. Determine whether all the working conditions to be checked have been traversed. If so, determine that the analysis result of the bus fault distance one-stage protection is not abnormal; if not, execute steps C2 to C4.

5. The method for analyzing relay protection anomaly according to any one of claims 2 to 4, characterized in that: The step of determining the ideal simulation parameters corresponding to the working condition to be verified includes: Determining simulation parameters to be adjusted and target electrical quantities corresponding to the working condition to be verified, wherein the simulation parameters to be adjusted include multiple simulation values; Determining the simulation value of the target electrical quantity corresponding to the simulation value of each simulation parameter to be adjusted in sequence, until it is determined that the cosine similarity between the simulation value of the target electrical quantity and the theoretical value of the target electrical quantity is within a preset similarity interval; The simulation value of the simulation parameter to be adjusted corresponding to the simulation value of the target electrical quantity in the preset similarity interval having a cosine similarity with the theoretical value of the target electrical quantity is determined as the ideal simulation parameter.

6. The relay protection abnormality analysis method according to claim 1, characterized in that: The determining whether there is an abnormality in relay protection based on the line differential protection analysis result, the variable speed pumped storage side failure protection analysis result and the busbar fault distance one section protection analysis result comprises: Determine whether the line differential protection analysis result, the variable speed pumped storage side failure protection analysis result, and the busbar fault distance protection analysis result are all normal; If yes, determine that there is no abnormality in the relay protection; if no, determine that there is an abnormality in the relay protection.

7. A relay protection abnormality analysis device for a variable speed pumped storage unit connected to a power grid, characterized in that: include: The electromagnetic transient analysis model construction module is configured to construct an electromagnetic transient analysis model based on the access grid, access line and simulation tool of the variable speed pumped storage unit, wherein the electromagnetic transient analysis model is used to simulate the variable speed pumped storage unit, the access grid and the access line; the electromagnetic transient analysis model is controlled by an AC excitation controller connected to the simulation tool; The relay protection abnormality analysis module is configured to perform line differential protection analysis operations, variable speed pumped storage side failure protection analysis operations and busbar fault distance one section protection analysis operations on the variable speed pumped storage unit based on the AC excitation controller and the electromagnetic transient analysis model, and determine the line differential protection analysis results, the variable speed pumped storage side failure protection analysis results and the busbar fault distance one section protection analysis results; The relay protection abnormality determination module is configured to determine whether there is an abnormality in the relay protection based on the line differential protection analysis result, the variable speed pumped storage side failure protection analysis result and the busbar fault distance protection analysis result.

8. The relay protection abnormality analysis device according to claim 7, characterized in that: The relay protection abnormality analysis module includes a line differential protection analysis unit, which is configured to perform a line differential protection analysis operation, wherein the steps of the line differential protection analysis operation include: A1. Determine a plurality of working conditions to be verified corresponding to the line differential protection analysis operation; A2. Determine the ideal simulation parameters corresponding to the working condition to be verified, wherein the ideal simulation parameters are used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the working condition to be verified; A3. Based on the AC excitation controller and the ideal simulation parameters, determine the current line differential protection fault current and the current line differential protection fault voltage of the electromagnetic transient analysis model under the working condition to be verified; A4, determine whether the current line differential protection fault current is less than the previous line differential protection fault current and whether the current line differential protection fault voltage is greater than the previous line differential protection fault voltage. If so, determine the current line differential protection fault current and the current line differential protection fault voltage as the line differential protection check value, and execute A5; if not, determine the previous line differential protection fault current and the previous line differential protection fault voltage as the line differential protection check value, and execute A5; A5. Determine whether to traverse all the working conditions to be verified. If so, determine the line differential protection analysis result based on the line differential protection setting value and the line differential protection verification value; if not, execute A2 to A4.

9. The relay protection abnormality analysis device according to claim 7, characterized in that: The relay protection abnormality analysis module includes a variable speed pumped storage side failure protection analysis unit, which is configured to perform a variable speed pumped storage side failure protection analysis operation, wherein the steps of the variable speed pumped storage side failure protection analysis operation include: B1. Determine a plurality of working conditions to be verified corresponding to the variable speed pumped storage side failure protection analysis operation; B2. Determine the ideal simulation parameters corresponding to the working condition to be verified, wherein the ideal simulation parameters are used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the working condition to be verified; B3. Based on the AC excitation controller and the ideal simulation parameters, determine the current variable speed pumped storage side failure protection fault current of the electromagnetic transient analysis model under the working condition to be verified; B4, determining whether the current variable speed pumped storage side failure protection fault current is less than the previous variable speed pumped storage side failure protection fault current, if so, determining the current variable speed pumped storage side failure protection fault current as the variable speed pumped storage side failure protection check value, and executing B5; if not, determining the previous variable speed pumped storage side failure protection fault current as the variable speed pumped storage side failure protection check value, and executing B5; B5. Determine whether all the working conditions to be verified are traversed. If so, determine the analysis result of the variable speed pumped storage side failure protection based on the variable speed pumped storage side failure protection setting value and the variable speed pumped storage side failure protection verification value; if not, execute B2 to B4.

10. The relay protection abnormality analysis device according to claim 7, characterized in that: The relay protection abnormality analysis module includes a bus fault distance one section protection analysis unit, which is configured to perform a bus fault distance one section protection analysis operation, wherein the steps of the bus fault distance one section protection analysis operation include: C1. Determine a plurality of working conditions to be verified corresponding to the busbar fault distance one-segment protection analysis operation; C2. Determine the ideal simulation parameters corresponding to the working condition to be verified, wherein the ideal simulation parameters are used to adjust the current power flow distribution of the electromagnetic transient analysis model to be consistent with the power flow distribution of the working condition to be verified; C3. Based on the AC excitation controller and the ideal simulation parameters, determine the current bus fault distance one section protection fault current and the current bus fault distance one section protection fault voltage of the electromagnetic transient analysis model under the working condition to be verified; C4, based on the waveform of the current bus fault distance one section protection fault current and the waveform of the current bus fault distance one section protection fault voltage, determine whether the distance protection device is reliable and does not operate under the working condition to be verified, if so, execute C5; if not, determine that the bus fault distance one section protection analysis result is abnormal; C5. Determine whether all the working conditions to be checked have been traversed. If so, determine that the analysis result of the bus fault distance one-stage protection is not abnormal; if not, execute steps C2 to C4.

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 relay protection anomalies of a variable-speed pumped storage unit connected to a power grid as described in any one of claims 1 to 6 are implemented.

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 relay protection anomalies of a variable-speed pumped storage unit connected to a power grid as described in any one of claims 1 to 6 are implemented.

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 relay protection anomalies of a variable-speed pumped storage unit connected to a power grid as described in any one of claims 1 to 6 are implemented.

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