Performance test system of current transformer on-line monitoring device

Abstract

The invention relates to a performance test system of a current transformer on-line monitoring device. The system comprises a power supply module, a current transformer simulation module, a difference value proportion module and a control module, wherein the power supply module is used for providing primary current for the current transformer simulation module; the current transformer simulation module is used for detecting primary current to obtain secondary current; the control module is used for sending a differential signal generation parameter to the difference value proportion module according to the test instruction; the difference proportion module is used for generating a differential signal according to the differential signal generation parameter, superposing the differential signal and the secondary current to obtain a test signal for the current transformer online monitoring device, and inputting the test signal to the current transformer online monitoring device; the control module is also used for obtaining an output result of the current transformer online monitoring device after obtaining the test signal, and obtaining a performance test result according to the output result and the differential signal. The performance test of the current transformer on-line monitoring device can be rapidly realized.

Description

Technical Field

[0001] This application relates to the technical field of current transformer metering, and particularly to a performance test system for an on-line monitoring device of a current transformer. Background Art

[0002] As a key metering instrument in the power system, current transformers are widely used in fields such as power trade settlement, measuring instruments, and relay protection. It is directly related to the safe and stable operation of the power grid and fair electricity trading, etc. Therefore, on-line monitoring of current transformers to determine whether the operating state of the equipment is accurate is of great significance for the normal operation of current transformers, and further determines the reliability of power grid power supply and the accuracy of electric energy metering devices. Currently, those skilled in the art usually monitor the state of current transformers through on-line monitoring devices of current transformers to achieve functions such as error monitoring, state assessment, and operation and maintenance management of current transformers.

[0003] In the actual application of current transformer monitoring devices, it is necessary to test the accuracy and evaluation effect before use, and due to factors such as the service life of the device and the influence of the external environment, the accuracy of on-line monitoring devices of current transformers may be affected. Therefore, there is an urgent need for a performance test system for on-line monitoring devices of current transformers to test the monitoring accuracy of on-line monitoring devices of current transformers. Summary of the Invention

[0004] Based on this, in view of the above technical problems, it is necessary to provide a performance test system for an on-line monitoring device of a current transformer that can test the monitoring accuracy of the on-line monitoring device of the current transformer.

[0005] This application provides a performance test system for an on-line monitoring device of a current transformer. The system includes a power supply module, a current transformer simulation module, a difference ratio module, and a control module, where:

[0006] The power supply module is used to provide a primary current for the current transformer simulation module;

[0007] The current transformer simulation module is used to detect the primary current to obtain a secondary current and is used to simulate a current transformer;

[0008] The control module is used to send micro-difference signal generation parameters to the difference ratio module according to a test instruction; the micro-difference signal generation parameters include a current amplitude parameter and a current phase parameter;

[0009] The differential ratio module is used to generate a differential signal according to the differential signal generation parameter, superimpose the differential signal on the secondary current to obtain a test signal for the on-line monitoring device of the current transformer, and input the test signal into the on-line monitoring device of the current transformer;

[0010] The control module is further configured to obtain the output result of the on-line monitoring device of the current transformer after obtaining the test signal, and obtain a performance test result according to the output result and the differential signal.

[0011] In one embodiment, the power supply module includes a regulated power supply unit and a current boosting power supply unit;

[0012] The regulated power supply unit is used to provide three-phase current to the current boosting power supply unit;

[0013] The current boosting power supply unit is used to convert the three-phase current into a primary current; the value of the primary current is greater than the value of the single-phase current in the three-phase current.

[0014] In one embodiment, the control module is further configured to adjust the three-phase current according to the test instruction, so that the output frequency of the three-phase current is 50 Hz, the output voltage adjustment range is 0 V to 250 V, and the three-phase phase adjustment range is 0 degrees to 180 degrees.

[0015] In one embodiment, the current transformer simulation module includes a plurality of power CT simulation units and a plurality of circuit breakers associated with the power CT simulation units;

[0016] The circuit breaker is used to transmit the primary current to the corresponding power CT simulation unit;

[0017] The power CT simulation unit is used to obtain a secondary current based on the primary current;

[0018] The control module is further configured to switch the on-off state of the circuit breaker according to the test instruction to control the number of secondary currents received by the differential ratio module, and further control the number of test signals input into the on-line monitoring device of the current transformer.

[0019] In one embodiment, the current transformer simulation module further includes a plurality of standard CT comparison units, and the number of the standard CT comparison units is the same as the number of the power CT simulation units, and the standard CT comparison units are connected in series with the power CT simulation units;

[0020] The turns ratio of the standard CT comparison unit is the same as that of the power CT simulation unit. The standard CT comparison unit is used to obtain a standard secondary current based on the primary current and transmit the standard secondary current to the control module;

[0021] The control module is further used to perform error verification on the power CT simulation unit according to the standard secondary current.

[0022] In one embodiment, the standard CT comparison unit is further used to transmit the standard secondary current to the current transformer on-line monitoring device;

[0023] The control module is further used to obtain the channel measurement result of the on-line monitoring device for the standard secondary current, and perform channel error verification on the current transformer on-line monitoring device according to the channel measurement result and the standard secondary current.

[0024] In one embodiment, the control module is further used to perform error verification on the monitoring algorithm of the current transformer on-line monitoring device according to the standard secondary current and the performance test result.

[0025] In one embodiment, the control module is further used to control the difference ratio module to generate a number of differential signals that match the number of secondary currents detected by the multiple power CT simulation units;

[0026] The difference ratio module is further used to superimpose the matching differential signals on the secondary current to obtain a plurality of test signals, and input the plurality of test signals into the current transformer on-line monitoring device respectively.

[0027] In one embodiment, the current transformer simulation module includes a first power CT simulation unit, a second power CT simulation unit, a third power CT simulation unit, a fourth power CT simulation unit, a fifth power CT simulation unit, a sixth power CT simulation unit, and a first circuit breaker, a second circuit breaker, a third circuit breaker, a fourth circuit breaker, a fifth circuit breaker, a sixth circuit breaker, a seventh circuit breaker, and an eighth circuit breaker;

[0028] The first end of the first power CT simulation unit is connected to the first end of the power supply module. The second end of the first power CT simulation unit is connected to the first end of the first circuit breaker. The second end of the first circuit breaker is connected to the first end of the second circuit breaker. The second end of the second circuit breaker is connected to the first end of the second power CT simulation unit. The second end of the second power CT simulation unit is connected to the second end of the power supply module. The second end of the first circuit breaker is also connected to the first end of the third circuit breaker. The second end of the third circuit breaker is connected to the first end of the third power CT simulation unit. The second end of the third power CT simulation unit is connected to the third end of the power supply module. The first end of the first power CT simulation unit is also connected to the fourth end of the power supply module. The fourth end of the power supply module is also connected to the first end of the fourth circuit breaker. The second end of the fourth circuit breaker is connected to the first end of the fourth power CT simulation unit. The second end of the fourth power CT simulation unit is connected to the first end of the fifth circuit breaker. The second end of the fifth circuit breaker is connected to the first end of the sixth circuit breaker. The second end of the sixth circuit breaker is connected to the first end of the fifth power CT simulation unit. The second end of the fifth power CT simulation unit is connected to the fifth end of the power supply module. The first end of the fourth power CT simulation unit is also connected to the sixth end of the power supply module. The first end of the fourth power CT simulation unit is also connected to the seventh end of the power supply module. The second end of the fifth circuit breaker is also connected to the first end of the seventh circuit breaker. The second end of the seventh circuit breaker is connected to the first end of the sixth power CT simulation unit. The second end of the sixth power CT simulation unit is connected to the eighth end of the power supply. The first end of the third circuit breaker is also connected to the first end of the eighth circuit breaker. The second end of the eighth circuit breaker is connected to the first end of the sixth circuit breaker;

[0029] The first end and the second end of the power supply module are used to provide a first primary current. The third end and the fourth end of the power supply module are used to provide a second primary current. The fifth end and the sixth end of the power supply module are used to provide a third primary current. The seventh end and the eighth end of the power supply module are used to provide a fourth primary current;

[0030] The first power CT simulation unit, the second power CT simulation unit, the third power CT simulation unit, the fourth power CT simulation unit, the fifth power CT simulation unit, and the sixth power CT simulation unit all include a detection output end, and the detection output end is used to output a secondary current to the difference ratio module;

[0031] The control module is further configured to switch the on / off states of the first circuit breaker, the second circuit breaker, the third circuit breaker, the fourth circuit breaker, the fifth circuit breaker, the sixth circuit breaker, the seventh circuit breaker, and the eighth circuit breaker respectively according to the test instructions, so as to change the secondary currents output by the first power CT simulation unit, the second power CT simulation unit, the third power CT simulation unit, the fourth power CT simulation unit, the fifth power CT simulation unit, and the sixth power CT simulation unit.

[0032] In one embodiment, the current transformer simulation module further includes a first standard CT comparison unit, a second standard CT comparison unit, a third standard CT comparison unit, a fourth standard CT comparison unit, a fifth standard CT comparison unit, and a sixth standard CT comparison unit, wherein,

[0033] The first end of the first standard CT comparison unit is connected to the second end of the first power CT simulation unit, the second end of the first standard CT comparison unit is connected to the first end of the first circuit breaker, the first end of the second standard CT comparison unit is connected to the second end of the second power CT simulation unit, the second end of the second standard CT comparison unit is connected to the second end of the power supply module, the first end of the third standard CT comparison unit is connected to the second end of the third power CT simulation unit, the second end of the third standard CT comparison unit is connected to the third end of the power supply module, the first end of the fourth standard CT comparison unit is connected to the second end of the fourth power CT simulation unit, the second end of the fourth standard CT comparison unit is connected to the first end of the fifth circuit breaker, the first end of the fifth standard CT comparison unit is connected to the second end of the fifth power CT simulation unit, the second end of the fifth standard CT comparison unit is connected to the fifth end of the power supply module, the first end of the sixth standard CT comparison unit is connected to the second end of the sixth power CT simulation unit, and the second end of the sixth standard CT comparison unit is connected to the eighth end of the power supply module.

[0034] The performance test system of the above on-line current transformer monitoring device provides a primary current for the current transformer simulation module through the power supply module, detects the primary current through the current transformer simulation module to obtain a secondary current, so as to simulate the current transformer. The control module sends a differential signal generation parameter to the differential ratio module according to the test instruction; the above differential signal generation parameter includes a current amplitude parameter and a current phase parameter; the differential ratio module generates a differential signal according to the above differential signal generation parameter, and superimposes the above differential signal with the above secondary current to obtain a test signal for the on-line current transformer monitoring device, and inputs the above test signal into the above on-line current transformer monitoring device; the control module obtains the output result of the above on-line current transformer monitoring device after obtaining the above test signal, and obtains a performance test result according to the above output result and the above differential signal; in this application, a current transformer model with a changeable error state is constructed through the current transformer simulation module and the differential ratio unit, so as to perform a performance test on the on-line current transformer monitoring device through test signals representing different error states, and the monitoring performance of the current sensor on-line monitoring device under different working conditions can be accurately evaluated. Description of the Drawings

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following will briefly introduce the drawings required for the description of the embodiments of the present application or related technologies. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0036] Figure 1 It is the first schematic structural diagram of the performance test system of the on-line current transformer monitoring device in an embodiment;

[0037] Figure 2 It is the second schematic structural diagram of the performance test system of the on-line current transformer monitoring device in an embodiment;

[0038] Figure 3 It is the third schematic structural diagram of the performance test system of the on-line current transformer monitoring device in another embodiment. Detailed Description of the Embodiments

[0039] In order to make the purpose, technical solutions and advantages of the present application more clear, the following will further describe the present application in detail in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present application, and are not used to limit the present application.

[0040] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element and integrated with it, or there may be an intermediate element present. The terms "disconnected", "one end", "the other end" and similar expressions used in this article are only for illustrative purposes.

[0041] Unless otherwise defined, all technical and scientific terms used in this article have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used in the description of this application in this article are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in this article includes any and all combinations of one or more of the related listed items.

[0042] In addition, if the terms "first" and "second" appear, these terms are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0043] In this application, unless otherwise clearly specified and limited, if terms such as "installed", "connected", "connected to", "fixed" appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0044] In order to be able to perform performance tests on the on-line monitoring device of the current transformer to test the monitoring accuracy of the on-line monitoring device of the current transformer, the embodiment of this application provides a performance test system for the on-line monitoring device of the current transformer, as Figure 1 shown. The above system includes a power supply module 110, a current transformer simulation module 120, a difference ratio module 130, and a control module 140, where:

[0045] The above power supply module 110 is used to provide a primary current for the above current transformer simulation module 120.

[0046] Among them, the power supply module can be an adjustable AC power supply, capable of generating a primary current signal with a preset amplitude and frequency. The primary current can refer to the current flowing on the input side of the current transformer, which is the untransformed current and is usually a large current. That is to say, the primary current is the original signal to be measured by the current transformer. In this embodiment, the primary current can refer to the current input from the power supply module 110 to the current transformer simulation module 120.

[0047] The above-mentioned current transformer simulation module 120 is used to detect the above-mentioned primary current to obtain a secondary current, for simulating a current transformer.

[0048] Among them, the current transformer simulation module 120 is used to simulate the behavior of the current transformer. It can detect the input primary current (large current) and output the corresponding secondary current (small current) to realize the reproduction of the current transformer function. For detecting the above-mentioned primary current to obtain a secondary current can mean that after receiving the primary current, the current transformer simulation module 120 can perform processing and conversion to obtain the secondary current. A current transformer is an electrical device used to measure alternating current, capable of converting a high current signal into a smaller, proportional current signal for easy measurement and monitoring. The current transformer simulation module 120 provides a real input signal for subsequent tests by simulating the working state of the current transformer in actual applications.

[0049] The above-mentioned control module 140 is used to send micro-difference signal generation parameters to the above-mentioned difference ratio module 130 according to the test instruction; the micro-difference signal generation parameters include current amplitude parameters and current phase parameters.

[0050] Among them, the control module 140 can have a supporting preset software. The user can select a preset error scheme through the preset software, and can also set a custom error scheme through the preset software. Then the software inputs the program corresponding to the preset scheme or the custom scheme into the control module 140. The control module 140 executes according to the test instruction included in the above program, and the control module 140 sends the micro-difference signal generation parameters obtained during the program execution process to the difference ratio module 130. The preset error scheme or the custom error scheme can be used to preset the error of the analog current transformer, and this error can be used for the online monitoring error assessment of the current transformer on-line monitoring device to be tested. The micro-difference signal generation parameters can include current amplitude parameters and current phase parameters, and these parameters are used to comprehensively simulate the signal characteristics output by the current transformer and are an important basis for test signal generation.

[0051] The above differential ratio module 130 is used to generate a differential signal according to the above differential signal generation parameters, superimpose the above differential signal on the above secondary current to obtain a test signal for the on-line monitoring device of the current transformer, and input the above test signal into the on-line monitoring device of the current transformer.

[0052] Among them, the differential signal may refer to a current signal generated by the differential ratio module according to the differential signal generation parameters. This current signal is used to be superimposed on the secondary current output by the current transformer simulation module 120 to obtain a test signal for performing a performance test on the on-line monitoring device of the current transformer, and then the test signal is input into the on-line monitoring device of the current transformer. The test signal is used to simulate the error current signals that may occur in different current transformers in the actual scenario, so as to evaluate the monitoring performance of the on-line monitoring device of the current transformer. In addition, the current amplitude parameter and current phase parameter used to generate the differential signal can be used to calculate the ratio error and phase error. Both the ratio error and phase error are important indicators describing the performance of the current transformer. Therefore, the accuracy of current transformer monitoring can be determined through the differential signal.

[0053] In the embodiment of the present application, the on-line monitoring device of the current transformer is the device to be tested. For any existing on-line monitoring device of the current transformer, the present application only needs to determine its monitoring error (monitoring performance) according to the data it displays, without considering how it realizes error monitoring.

[0054] The above control module 140 is further used to obtain the output result of the on-line monitoring device of the current transformer after obtaining the above test signal, and obtain a performance test result according to the above output result and the above differential signal.

[0055] Among them, the error characteristics of the current transformer can be evaluated through the on-line monitoring device. The evaluation ability of the on-line monitoring device for the error characteristics of the current transformer can be evaluated by the above performance test system for the monitoring error characteristics of the on-line monitoring device.

[0056] Among them, the output result may refer to the evaluation result output by the on-line monitoring device of the current transformer after receiving the test signal and evaluating the error of the current transformer represented by the test signal.

[0057] Among them, the performance test result may refer to the final index obtained by the control module through comprehensive analysis of the output result and the differential signal, and is used to characterize the monitoring error characteristics of the on-line monitoring device of the current transformer.

[0058] Exemplarily, after the on-line monitoring device of the current transformer receives a test signal, it outputs the error evaluation result of the current transformer represented by the test signal. The control module 140 calculates the theoretical error of the current transformer represented by the test signal according to the differential signal, and then according to the actual error evaluation result and the calculated theoretical error, the monitoring error characteristic of the on-line monitoring device of the current transformer, that is, the performance test result, can be obtained.

[0059] The performance test system of the above on-line monitoring device of the current transformer constructs a current transformer model with a changeable error state through the current transformer simulation module and the difference ratio unit, so as to perform a performance test on the on-line monitoring device of the current transformer through test signals representing different error states, and can accurately evaluate the monitoring performance of the on-line monitoring device of the current sensor under different working conditions. In addition, the differential ratio module can generate a differential signal containing accurate current amplitude and current phase, which can improve the accuracy and reliability of the performance test.

[0060] In an exemplary embodiment, the above power supply module includes a voltage stabilizing and regulating power supply unit and a current boosting power supply unit; the voltage stabilizing and regulating power supply unit is used to provide three-phase current to the current boosting power supply unit; the current boosting power supply unit is used to convert the three-phase current into a primary current; the value of the primary current is greater than the value of the single-phase current in the three-phase current.

[0061] Among them, the voltage stabilizing and regulating power supply unit may refer to a power supply device that provides stable voltage and current output. In this embodiment, it may be used to provide stable and reliable three-phase current to the current boosting power supply unit. The current boosting power supply unit may refer to a power supply device that amplifies the input current to a higher value. In this embodiment, the current boosting power supply unit receives the three-phase current from the voltage stabilizing and regulating power supply unit and converts it into a primary current with a higher current value for simulating the primary current input of the current transformer.

[0062] Exemplarily, the voltage stabilizing and regulating power supply unit can receive an external power supply input (such as commercial power), and through an internal voltage stabilizing circuit and adjustment mechanism, generate stable and adjustable three-phase alternating current. The voltage stabilizing and regulating power supply unit may include components such as a transformer, a rectifier, a filter, and a voltage regulator to ensure the stability and accuracy of the output current. The current boosting power supply unit receives the three-phase current from the voltage stabilizing and regulating power supply unit, and through a special circuit design (such as a transformer, a current amplifier, etc.), amplifies the current value to the required primary current level, that is, the value of the primary current is greater than the value of the single-phase current in the three-phase current, to ensure that the simulated primary current is large enough to effectively perform subsequent tests.

[0063] In this embodiment, through the combination of the regulated power supply unit and the current-boosting power supply unit, a stable, reliable, and adjustable primary current source can be provided for the performance test system of the current transformer on-line monitoring device, ensuring the stability and reliability of the current source during the test, reducing the impact of power fluctuations on the test results, thereby achieving more accurate and comprehensive performance evaluation, and improving the efficiency and safety of the test.

[0064] In an exemplary embodiment, the above control module is further configured to adjust the above three-phase current according to the above test instruction, so that the output frequency of the above three-phase current is 50 Hz, the output voltage adjustment range is 0 V to 250 V, and the three-phase phase adjustment range is 0 degrees to 180 degrees.

[0065] Among them, the test instruction can be used to specify the parameters of the test, such as the output frequency of the three-phase current, the output voltage adjustment range, the three-phase phase adjustment range, and other test-related settings.

[0066] Exemplarily, the control module receives the test instruction, and performs frequency adjustment, voltage adjustment, and phase adjustment through the frequency, voltage, and phase parameters of the required three-phase current included in the instruction, so that the output frequency of the three-phase current is 50 Hz, the output voltage adjustment range is 0 V to 250 V, and the three-phase phase adjustment range is 0 degrees to 180 degrees.

[0067] In this embodiment, by adjusting the frequency, voltage, and phase of the three-phase current through the test instruction, various power system conditions can be simulated, such as normal operation, voltage fluctuation, frequency deviation, unbalanced load, etc., so that the performance test system can more comprehensively evaluate the monitoring performance of the current transformer on-line monitoring device under different conditions.

[0068] In an exemplary embodiment, the above current transformer simulation module includes a plurality of power CT simulation units and a plurality of circuit breakers associated with the above power CT simulation units;

[0069] The above circuit breaker is used to transmit the above primary current to the corresponding above power CT simulation unit;

[0070] The above power CT simulation unit is used to obtain a secondary current based on the above primary current;

[0071] The above control module is further configured to switch the on-off state of the above circuit breaker according to the test instruction, so as to control the number of secondary currents received by the above difference ratio module, and further control the number of test signals input to the above current transformer on-line monitoring device.

[0072] Among them, the power CT (Current Transformer) simulation unit can be used to simulate an independent current transformer. Each power CT simulation unit receives a primary current input and generates a corresponding secondary current output. The circuit breaker can be a switching device used to control the on / off of the circuit. In this embodiment, the circuit breaker can be used to control whether the primary current flows through the corresponding power CT simulation unit, thereby controlling the power CT simulation unit to generate a secondary current.

[0073] Exemplarily, the circuit breaker transmits the primary current to the corresponding power CT simulation unit. The control module controls the on / off state of each circuit breaker according to the test instruction. By controlling the on / off states of multiple circuit breakers, the control module can control some or all of the power CT simulation units to generate secondary currents, so as to control the number of secondary currents received by the differential ratio module. For example, if all circuit breakers are closed, all power CT simulation units will generate secondary currents; if only some circuit breakers are closed, only some associated power CT simulation units will generate secondary currents. The control module controls the number of secondary currents received by the differential ratio module, which also controls the number of test signals output by the differential ratio module. For example, the differential ratio module receives 18 secondary currents. The differential ratio module generates a differential signal for each secondary current, then superimposes each secondary current with the corresponding differential signal to generate 18 test signals, and then inputs the 18 test signals into the 18 measurement channels of the current transformer on-line monitoring device respectively, which is equivalent to simulating the scenario where the current transformer on-line monitoring device monitors 18 current transformers at the same time, and can test the monitoring performance of the current transformer on-line monitoring device when monitoring these current transformers under different numbers of current transformer configurations in the power system.

[0074] In this embodiment, the control module controls the number of secondary currents received by the differential ratio module by controlling the circuit breaker, and further controls the number of test signals input into the above current transformer on-line monitoring device, that is, it can flexibly select some or all of the multiple power CT simulation units to participate in the test, so as to generate different numbers and combinations of test signals, enabling the performance test system to simulate various complex power system conditions, thereby more comprehensively evaluating the monitoring performance of the current transformer on-line monitoring device and improving the accuracy of the test.

[0075] In an exemplary embodiment, the above current transformer simulation module further includes a plurality of standard CT comparison units, and the number of the above standard CT comparison units is the same as the number of the above power CT simulation units. The above standard CT comparison units are connected in series with the above power CT simulation units;

[0076] The turns ratio of the above-mentioned standard CT comparison unit is the same as that of the above-mentioned power CT simulation unit. The above-mentioned standard CT comparison unit is used to obtain a standard secondary current based on the above-mentioned primary current and transmit the above-mentioned standard secondary current to the above-mentioned control module;

[0077] The above-mentioned control module is further used to perform error verification on the above-mentioned power CT simulation unit according to the above-mentioned standard secondary current.

[0078] Among them, the standard CT (Current Transformer) comparison unit is a device that simulates a high-precision current transformer and is used to provide a reference secondary current for error verification of the output of the power CT simulation unit. In this embodiment, the standard CT comparison unit is connected in series with the power CT simulation unit, receives the same primary current, and generates a high-precision secondary current, that is, the standard secondary current. The control module compares whether the output of the power CT simulation unit is accurate based on this standard secondary current and corrects it to improve the accuracy of the power CT simulation unit.

[0079] In an exemplary embodiment, the above-mentioned standard CT comparison unit is further used to transmit the above-mentioned standard secondary current to the above-mentioned current transformer on-line monitoring device;

[0080] The above-mentioned control module is further used to obtain the channel measurement results of the above-mentioned on-line monitoring device for the above-mentioned standard secondary current, and perform channel error verification on the above-mentioned current transformer on-line monitoring device according to the above-mentioned channel measurement results and the above-mentioned standard secondary current.

[0081] Among them, the channel measurement result may refer to the measurement value of each measurement channel of the current transformer on-line monitoring device for the input signal (in this embodiment, the standard secondary current). The channel measurement result reflects the measurement accuracy and response characteristics of the current transformer on-line monitoring device for the input signal and is the basis for evaluating the channel error. The channel error may refer to the deviation between the measurement value of a certain measurement channel of the current transformer on-line monitoring device and the actual input value; by verifying and correcting the channel error, the measurement accuracy and reliability of the current transformer on-line monitoring device can be improved, and the influence of the channel error on the performance test can be avoided.

[0082] In an exemplary embodiment, the above-mentioned control module is further used to perform error verification on the monitoring algorithm of the above-mentioned current transformer on-line monitoring device according to the above-mentioned standard secondary current and the above-mentioned performance test results.

[0083] Among them, the performance test result can refer to the final index obtained by the control module through comprehensive analysis of the output result and the differential signal, and is used to characterize the monitoring error characteristics of the current transformer on-line monitoring device. The output result can refer to the evaluation result output by the current transformer on-line monitoring device after receiving the test signal and calculating and evaluating the error of the current transformer represented by the test signal through the internal monitoring algorithm.

[0084] Exemplarily, the control module can obtain the monitoring error of the monitoring algorithm of the current transformer on-line monitoring device through the performance test result, then input the standard secondary current into the current transformer on-line monitoring device to obtain the output result corresponding to the standard secondary current, and then verify the error of the monitoring algorithm according to the output result corresponding to the standard secondary current and the monitoring error obtained according to the performance test result.

[0085] In this embodiment, the control module can verify the error of the monitoring algorithm of the current transformer on-line monitoring device through the standard secondary current and the performance test result, can timely discover the defects and deficiencies in the monitoring algorithm, and provide a basis for the improvement and optimization of the algorithm.

[0086] In an exemplary embodiment, the above control module is further configured to control the above differential ratio module to generate a number of differential signals matching the number of secondary currents detected by the plurality of above power CT simulation units; the above differential ratio module is further configured to superimpose the matched differential signals on the secondary current to obtain a plurality of test signals, and input the plurality of test signals into the above current transformer on-line monitoring device respectively.

[0087] Among them, the control module needs to first determine each power CT simulation unit participating in the test, that is, each power CT simulation unit that outputs secondary current, then determine the secondary currents of each path that need to be superimposed with differential signals according to the test instruction, and then the differential ratio module generates a plurality of differential signals corresponding to each path of secondary current according to the instruction of the control module, and then superimposes a corresponding set of differential signals and secondary current to obtain a plurality of test signals, and finally inputs the plurality of test signals through different measurement channels of the current transformer on-line monitoring device respectively.

[0088] In this embodiment, the control module can obtain a plurality of test signals by matching differential signals for the secondary currents output by different power CT simulation units, which can improve the sensitivity and refinement degree of the test.

[0089] In an exemplary embodiment, such as Figure 2As shown, the above current transformer simulation module includes a first power CT simulation unit 201, a second power CT simulation unit 202, a third power CT simulation unit 203, a fourth power CT simulation unit 204, a fifth power CT simulation unit 205, a sixth power CT simulation unit 206, as well as a first circuit breaker 211, a second circuit breaker 212, a third circuit breaker 213, a fourth circuit breaker 214, a fifth circuit breaker 215, a sixth circuit breaker 216, a seventh circuit breaker 217, and an eighth circuit breaker 218.

[0090] The first end of the first power CT simulation unit 201 is connected to the first end 221 of the power supply module. The second end of the first power CT simulation unit 201 is connected to the first end of the first circuit breaker 211. The second end of the first circuit breaker 211 is connected to the first end of the second circuit breaker 212. The second end of the second circuit breaker 212 is connected to the first end of the second power CT simulation unit 202. The second end of the second power CT simulation unit 202 is connected to the second end 222 of the power supply module. The second end of the first circuit breaker 211 is also connected to the first end of the third circuit breaker 213. The second end of the third circuit breaker 213 is connected to the first end of the third power CT simulation unit 203. The second end of the third power CT simulation unit 203 is connected to the third end 223 of the power supply module. The first end of the first power CT simulation unit 201 is also connected to the fourth end 224 of the power supply module. The fourth end 224 of the power supply module is also connected to the first end of the fourth circuit breaker 214. The second end of the fourth circuit breaker 214 is connected to the first end of the fourth power CT simulation unit 204. The second end of the fourth power CT simulation unit 204 is connected to the first end of the fifth circuit breaker 215. The second end of the fifth circuit breaker 215 is connected to the first end of the sixth circuit breaker 216. The second end of the sixth circuit breaker 216 is connected to the first end of the fifth power CT simulation unit 205. The second end of the fifth power CT simulation unit 205 is connected to the fifth end 225 of the power supply module. The first end of the fourth power CT simulation unit 204 is also connected to the sixth end 226 of the power supply module. The first end of the fourth power CT simulation unit 204 is also connected to the seventh end 227 of the power supply module. The second end of the fifth circuit breaker 215 is also connected to the first end of the seventh circuit breaker 217. The second end of the seventh circuit breaker 217 is connected to the first end of the sixth power CT simulation unit 206. The second end of the sixth power CT simulation unit 206 is connected to the eighth end 228 of the power supply. The first end of the third circuit breaker 213 is also connected to the first end of the eighth circuit breaker 218. The second end of the eighth circuit breaker 218 is connected to the first end of the sixth circuit breaker 216.

[0091] The first end 221 and the second end 222 of the above power supply module are used to provide a first primary current. The third end 223 and the fourth end 224 of the above power supply module are used to provide a second primary current. The fifth end 225 and the sixth end 226 of the above power supply module are used to provide a third primary current. The seventh end 227 and the eighth end 228 of the above power supply module are used to provide a fourth primary current. Among them, Figure 2 231 in it can refer to the AC output function module of the power supply module. The first end 221 and the second end 222 of the power supply module can be used as a single-phase output port to provide the first primary current to the subsequent circuit. The third end 223 and the fourth end 224 of the power supply module can be used as another single-phase output port to provide the second primary current to the subsequent circuit. The fifth end 225 and the sixth end 226 of the power supply module can be used as yet another single-phase output port to provide the third primary current to the subsequent circuit. The seventh end 227 and the eighth end 228 of the power supply module can be used as still another single-phase output port to provide the fourth primary current to the subsequent circuit. Among them, the power supply module can input commercial power, industrial power, or other power sources. The power supply module converts the input power into multiple sets of three-phase outputs for the subsequent circuit to use.

[0092] The above first power CT simulation unit 201, the above second power CT simulation unit 202, the above third power CT simulation unit 203, the above fourth power CT simulation unit 204, the above fifth power CT simulation unit 205, and the above sixth power CT simulation unit 206 all include a detection output end, and the detection output end is used to output a secondary current to the above difference ratio module; among them, the detection output end of the power CT simulation unit is Figure 2 not shown in all of them.

[0093] The above control module is further used to respectively switch the on-off states of the above first circuit breaker 211, the above second circuit breaker 212, the above third circuit breaker 213, the above fourth circuit breaker 214, the above fifth circuit breaker 215, the above sixth circuit breaker 216, the above seventh circuit breaker 217, and the above eighth circuit breaker 218 according to the test instruction, so as to change the secondary current output by the above first power CT simulation unit 201, the above second power CT simulation unit 202, the above third power CT simulation unit 203, the above fourth power CT simulation unit 204, the above fifth power CT simulation unit 205, and the above sixth power CT simulation unit 206.

[0094] Exemplarily, such as Figure 2The power topology structure shown has a simulated power line consisting of two busbars, namely Busbar ⅠM and Busbar ⅡM, and four lines, namely Line Ⅰ-1, Line Ⅰ-2, Line Ⅰ-3, and Line Ⅰ-4. The principle is to generate current on the lines, and the current on the busbar is the sum of the line currents. According to the KCL (Kirchhoff's Current Law), the busbar current is equal to the sum of the line currents, providing a basis for the error assessment of the on-line monitoring device for current transformers. Additionally, the switching of the circuit breaker can be controlled by the control module to achieve the switching of the primary circuit connection mode, and the accuracy of the error assessment of the on-line monitoring device for current transformers under different power topology structures can be verified through different connection modes. The specific different connection modes include: when the control module controls both Circuit Breaker 214 and Circuit Breaker 218 to be disconnected, and the control module controls Circuit Breaker 211, Circuit Breaker 212, Circuit Breaker 213, Circuit Breaker 215, Circuit Breaker 216, and Circuit Breaker 217 to be all conducting, it is a two-in-two-out connection mode, that is, two busbars input and four lines output. That is, on Busbar ⅠM, there is the first primary current provided by the first end 221 and the second end 222 of the power supply module, and the second primary current provided by the third end 223 and the fourth end 224 of the power supply module. That is to say, the current passing through the first power CT simulation unit 201 is the current after the superposition of the first primary current and the second primary current; the current passing through Line Ⅰ-1 is the first primary current, that is, the current passing through the second power CT simulation unit 202 is the first primary current; the current passing through Line Ⅰ-1 is the second primary current, that is, the current passing through the third power CT simulation unit 203 is the second primary current. On Busbar ⅡM, there is the first primary current provided by the fifth end 225 and the sixth end 226 of the power supply module, and the second primary current provided by the seventh end 227 and the eighth end 228 of the power supply module. That is to say, the current passing through the fourth power CT simulation unit 204 is the current after the superposition of the third primary current and the fourth primary current; the current passing through Line Ⅱ-1 is the third primary current, that is, the current passing through the fifth power CT simulation unit 205 is the third primary current; the current passing through Line Ⅱ-2 is the fourth primary current, that is, the current passing through the sixth power CT simulation unit 206 is the fourth primary current. Another example is that if the control module controls Circuit Breaker 215 to be disconnected, and the control module controls Circuit Breaker 211, Circuit Breaker 212, Circuit Breaker 213, Circuit Breaker 214, Circuit Breaker 215, Circuit Breaker 216, Circuit Breaker 217, and Circuit Breaker 218 to be all conducting, it is a one-in-four-out connection mode, that is, one busbar inputs and four lines output.In addition, other topological structures can be formed by switching the circuit breakers, including: one input and one output (one bus input, one line output); one input and two outputs (one bus input, two line outputs); one input and three outputs (one bus input, three line outputs); two inputs and one output (two bus inputs, one line output for each bus); two inputs and three outputs (two bus inputs, two line outputs for one bus and one line output for the other bus); two inputs and four outputs (two bus inputs, two line outputs for each bus). In summary, as described above, Figure 2 The power topological structure shown can form the topological structures of the above eight connection modes by switching the circuit breakers, realizing the simulation of the topological relationship of the primary power system and more realistically simulating the operating environment of the current transformer.

[0095] In an exemplary embodiment, as Figure 2 shown, the above current transformer simulation module further includes a first standard CT comparison unit 241, a second standard CT comparison unit 242, a third standard CT comparison unit 243, a fourth standard CT comparison unit 244, a fifth standard CT comparison unit 245, and a sixth standard CT comparison unit 246. Among them, the first end of the first standard CT comparison unit 241 is connected to the second end of the first power CT simulation unit 201, the second end of the first standard CT comparison unit 241 is connected to the first end of the first circuit breaker 211, the first end of the second standard CT comparison unit 242 is connected to the second end of the second power CT simulation unit 202, the second end of the second standard CT comparison unit 242 is connected to the second end 222 of the power supply module, the first end of the third standard CT comparison unit 243 is connected to the second end of the third power CT simulation unit 203, the second end of the third standard CT comparison unit 243 is connected to the third end 223 of the power supply module, the first end of the fourth standard CT comparison unit 244 is connected to the second end of the fourth power CT simulation unit 204, the second end of the fourth standard CT comparison unit 244 is connected to the first end of the fifth circuit breaker 215, the first end of the fifth standard CT comparison unit 245 is connected to the second end of the fifth power CT simulation unit 205, the second end of the fifth standard CT comparison unit 245 is connected to the fifth end 225 of the power supply module, the first end of the sixth standard CT comparison unit 246 is connected to the second end of the sixth power CT simulation unit 206, and the second end of the sixth standard CT comparison unit 246 is connected to the eighth end 228 of the power supply module.

[0096] In this embodiment, the series connection mode of each standard CT comparison unit and the power CT simulation unit is as described above. The current received by each standard CT comparison unit is exactly the same as the current passing through the corresponding power CT simulation unit, which can ensure the consistency between the reference signal (the output signal of the standard CT comparison unit) and the simulation signal (the output signal of the power CT simulation unit) used in the test process. This provides a reliable basis for subsequent comparative tests and error analysis.

[0097] In an exemplary embodiment, as Figure 3 shown, a simulation test platform for an on-line monitoring device of a current transformer is provided, including: a regulated power supply unit 301, a current boosting power supply unit 302, a standard CT comparison unit 303, a power CT simulation unit 304, a difference ratio unit 305, and a control unit 306. Among them, the control unit is also configured with supporting software.

[0098] Please refer to Figure 3 and in combination with Figure 2 , the above-mentioned simulation test platform for the on-line monitoring device of the current transformer is used for current data acquisition and display inspection, channel relative error test, and evaluation of error characteristics of the on-line monitoring device of the current transformer. For example, in the test platform, when the power CT simulation units all meet the error requirements (in the initial state), the evaluation result output by the on-line monitoring device of the current transformer should be that the error is qualified; when the error of one or two simulated CTs is adjusted to an out-of-tolerance state through the difference ratio unit, the on-line monitoring device should be able to identify the out-of-tolerance current transformer.

[0099] Among them, the regulated power supply unit has 4 groups of three-phase voltage outputs (the other 2 groups Figure 3 are not shown), the output frequency is the power frequency of 50 Hz, the output voltage can be continuously adjusted from 0 - 250 V, and the three-phase phase can be adjusted from 0 - 180°, which is used as the input source of the current boosting power supply unit.

[0100] Among them, the number of current boosting power supply units is 4 groups of 12 ( Figure 3 2 groups of 6 are shown in

[0101] ), the current boosting power supply unit is a special transformer based on the electromagnetic principle, which changes the output voltage by changing the input voltage. The output voltage is applied to the primary circuit. Because there is impedance in the primary circuit, a current is formed in the primary circuit, which is used to simulate the adjustment of the primary current of the power system. Figure 2 Among them, the above-mentioned standard CT comparison unit is designed based on the electromagnetic principle, designed according to the characteristics of the standard current transformer, and the accuracy is controlled at 0.005S level, with a total of 6 groups of 18 ( Figure 3Three groups (9 in each group) are shown. The transformation ratio is the same as that of the power CT simulation unit, and it is connected in series with the power CT simulation unit on the same line, and is used to regularly check the error of the simulated power CT. The error of this unit is extremely small (0.005s level), which can be ignored for the on-line monitoring device of current transformers with a channel error of 0.05%. Therefore, its secondary current can be input into the on-line monitoring device of current transformers, so as to check the channel error of the device and verify the algorithm error of the device.

[0102] Among them, the power CT simulation unit is used to simulate the current transformer in the power system. It is designed based on the electromagnetic principle and designed according to the characteristics of the power current transformer. The accuracy is controlled within two-thirds of the limit error of 0.2S level, with a total of 6 groups and 18 units; the secondary current output by the power CT simulation unit is used as the input signal of the on-line monitoring device of current transformers; as Figure 2 shown, it is the topological structure principle of a simulation type test platform for on-line monitoring device of current transformers. Its principle is to generate current on the line, and the current on the bus is the sum of the line currents. According to the KCL (Kirchhoff's current law), the bus current is equal to the sum of the line currents, providing a basis for the error assessment of the on-line monitoring device of current transformers; at the same time, its connection form can be switched through the circuit breaker to form the following several topological structures:

[0103] 1) One input and one output - one bus input and one line output;

[0104] 2) One input and two outputs - one bus input and two line outputs;

[0105] 3) One input and three outputs - one bus input and three line outputs;

[0106] 4) One input and four outputs - one bus input and four line outputs;

[0107] 5) Two inputs and one output - two bus inputs, and one line output for each section of the bus;

[0108] 6) Two inputs and two outputs - two bus inputs, and one line output for each section of the bus;

[0109] 7) Two inputs and three outputs - two bus inputs, two line outputs for one section of the bus, and one line output for one section of the bus;

[0110] 8) Two inputs and four outputs - two bus inputs, and two line outputs for each section of the bus.

[0111] Among them, as Figure 3As shown, the differential ratio unit has a total of 18 channels and is used for the ratio adjustment of the power CT simulation unit. By superimposing the secondary current signals output by the 18-channel power CT simulation unit and the 18-channel differential signals through an isolation unit (not shown in the figure, built into the differential ratio unit, used to isolate and superimpose the secondary current signals and the differential signals), the differential signals can achieve programmed output of amplitude and phase. The differential ratio unit can be used to adjust the output current amplitude and phase of the 18-channel power CT simulation unit. Exemplarily, the differential signals can be based on a regulated power supply and a programmed voltage regulating power supply as the current amplitude and phase reference, and then the in-phase component (ratio) and the quadrature component (phase) are output, and accurate differential signals are obtained through signal synthesis. In addition, the ratio difference and phase difference can be obtained through the differential signals, which are used as real-time quantities for comparison with the relative quantity and the standard CT comparison unit, to know the true error state of the power CT simulation unit and formulate the threshold for the online monitoring device to identify.

[0112] Among them, the control unit is used to control the output of the three-phase voltage amplitude, phase, and frequency of the regulated power supply; it is also used for the regulated output of the 18-channel differential signals of the differential ratio unit; and it is used to cooperate with the management control program to implement the control of the preset scheme and the custom scheme. The supporting software in the control unit is used for the setting of the preset test scheme and the custom scheme, executed by the programmed control unit, for the acquisition of the detection results, the evaluation of the detection results, and the output of the report.

[0113] The above test platform can simulate the topological relationship diagram of the power system, such as the conversion of topological structures such as two inputs and two outputs, one input and four outputs, etc.; the output node current of the platform can be adjusted arbitrarily, and the error state of the current transformer can be judged by judging the relationship between the node source end and the current; it can also simulate the current relationship between three phases to judge the error state of the current transformer; it can also change the current phase relationship to judge the error state of the current transformer; a standard CT can be added for the error comparison of the simulated power transformer to test the error change state of the simulated power transformer, and the error evaluation of the current transformer online monitoring device can be verified according to the error state.

[0114] This application uses a device composed of 18 simulated power current transformers and 18 differential ratio units to adjust the output ratio and phase difference, simulating the error change state of power current transformers. For example, the simulation scheme can be set by itself. When the errors of 18 simulated power current transformers are qualified, an on-line monitoring device for current transformers is used for error evaluation. Then, by changing the errors of one or more simulated CTs to make them out of tolerance, and then checking whether the on-line monitoring device for current transformers can identify the out-of-tolerance transformers (that is, whether the out-of-tolerance transformers can be evaluated as warning, out-of-tolerance, etc. during error evaluation); it can also adjust the out-of-tolerance amount of one or more simulated CTs to identify the judgment threshold of the on-line current error monitoring device. However, there are also some boundary conditions: 1) The out-of-tolerance of transformers is a small-probability event, so a large number of transformers cannot be out of tolerance at the same time; 2) The out-of-tolerance state can be set to several modes, such as a small out-of-tolerance caused by slow changes in factors such as current transformer damage and aging, and a short-term out-of-tolerance caused by external interference, and then it returns to normal immediately. A primary current output power supply system that can be adjusted in real time is constructed through a regulated power supply unit and a current boosting power supply unit; by presetting 18 standard CT comparison units, the error change state of the simulated CT can be compared in real time to facilitate determining whether the current simulated CT is out of tolerance and confirming whether the evaluation of the on-line monitoring device for current transformers is correct; through the control unit, the switching of the primary circuit connection method is realized, and various connection methods such as one-in-four-out, two-in-two-out, and two-in-four-out are realized for topologically simulating the primary wiring method of electricity; through the control unit, the errors of 18 simulated current transformers are preset according to the preset scheme and the custom scheme for the error test and error characteristic evaluation of the on-line monitoring device for the error characteristics of the current transformer to be tested. This application uses simulated power current transformers and differential ratio units to form a power current transformer model with adjustable errors, and also changes the tidal direction of current input and output through a switching device, that is, a circuit breaker. That is, by opening and closing different circuit breakers, different topological relationships are formed, thereby changing the combined current state of the bus current; it can also simulate the topological relationship of the primary power system, more realistically simulate the CT operating environment, and through the control unit, adjust the primary current characteristics and change the errors of each simulated power current transformer, and the error characteristics of the on-line monitoring device for the error characteristics of the current transformer can be conveniently evaluated.

[0115] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope recorded in this application.

[0116] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims

1. A performance test system for a current transformer online monitoring device, characterized in that: The system includes a power supply module, a current transformer simulation module, a difference ratio module and a control module, wherein: The power supply module is used to provide a primary current to the current transformer simulation module; The current transformer simulation module is used to detect the primary current and obtain the secondary current for simulating the current transformer; The control module is used to send a differential signal generation parameter to the differential ratio module according to a test instruction; the differential signal generation parameter includes a current amplitude parameter and a current phase parameter; The difference ratio module is used to generate a differential signal according to the differential signal generation parameter, and superimpose the differential signal with the secondary current to obtain a test signal for the current transformer online monitoring device, and input the test signal to the current transformer online monitoring device; The control module is also used to obtain the output result of the current transformer online monitoring device after obtaining the test signal, and obtain the performance test result according to the output result and the differential signal.

2. The system according to claim 1, characterized in that The power supply module includes a voltage stabilizing and regulating power supply unit and a current boosting power supply unit; The voltage-stabilizing and regulating power supply unit is used to provide three-phase current to the current-boosting power supply unit; The current-boosting power supply unit is used to convert the three-phase current into a primary current; the value of the primary current is greater than the value of a single-phase current in the three-phase current.

3. The system according to claim 2, characterized in that The control module is also used to adjust the three-phase current according to the test instruction, so that the output frequency of the three-phase current is 50Hz, the output voltage adjustment range is 0V to 250V, and the three-phase phase adjustment range is 0 degree to 180 degrees.

4. The system according to claim 1, characterized in that The current transformer simulation module includes a plurality of power CT simulation units and a plurality of circuit breakers associated with the power CT simulation units; The circuit breaker is used to transmit the primary current to the corresponding power CT simulation unit; The power CT simulation unit is used to obtain a secondary current based on the primary current; The control module is also used to switch the on / off state of the circuit breaker according to the test instruction to control the amount of secondary current received by the difference ratio module, thereby controlling the amount of test signals input into the current transformer online monitoring device.

5. The system according to claim 4, characterized in that The current transformer simulation module further includes a plurality of standard CT comparison units, and the number of the standard CT comparison units is the same as the number of the power CT simulation units, and the standard CT comparison units are connected in series with the power CT simulation units; The transformation ratio of the standard CT comparison unit is the same as that of the power CT simulation unit, and the standard CT comparison unit is used to obtain a standard secondary current based on the primary current and transmit the standard secondary current to the control module; The control module is also used to perform error check on the power CT simulation unit according to the standard secondary current.

6. The system according to claim 5, characterized in that The standard CT comparison unit is also used to transmit the standard secondary current to the current transformer online monitoring device; The control module is also used to obtain a channel measurement result of the online monitoring device for the standard secondary current, and to verify a channel error of the current transformer online monitoring device according to the channel measurement result and the standard secondary current.

7. The system according to claim 5, characterized in that The control module is further used to perform error verification on the monitoring algorithm of the current transformer online monitoring device according to the standard secondary current and the performance test result.

8. The system according to claim 4, characterized in that The control module is further used to control the difference ratio module to generate a number of differential signals that matches the number of secondary currents detected by the plurality of power CT simulation units; The difference ratio module is also used to superimpose the matched differential signal with the secondary current to obtain multiple test signals, and input the multiple test signals into the current transformer online monitoring device respectively.

9. The system according to any one of claims 4 to 8, characterized in that: The current transformer simulation module includes a first power CT simulation unit, a second power CT simulation unit, a third power CT simulation unit, a fourth power CT simulation unit, a fifth power CT simulation unit, a sixth power CT simulation unit, and a first circuit breaker, a second circuit breaker, a third circuit breaker, a fourth circuit breaker, a fifth circuit breaker, a sixth circuit breaker, a seventh circuit breaker, and an eighth circuit breaker; The first end of the first power CT simulation unit is connected to the first end of the power module, the second end of the first power CT simulation unit is connected to the first end of the first circuit breaker, the second end of the first circuit breaker is connected to the first end of the second circuit breaker, the second end of the second circuit breaker is connected to the first end of the second power CT simulation unit, the second end of the second power CT simulation unit is connected to the second end of the power module, the second end of the first circuit breaker is also connected to the first end of the third circuit breaker, the second end of the third circuit breaker is connected to the first end of the third power CT simulation unit, the second end of the third power CT simulation unit is connected to the third end of the power module, the first end of the first power CT simulation unit is also connected to the fourth end of the power module, the fourth end of the power module is also connected to the first end of the fourth circuit breaker, the second end of the fourth circuit breaker is connected to the first end of the fourth power CT simulation unit The second end of the fourth power CT simulation unit is connected to the first end of the fifth circuit breaker, the second end of the fifth circuit breaker is connected to the first end of the sixth circuit breaker, the second end of the sixth circuit breaker is connected to the first end of the fifth power CT simulation unit, the second end of the fifth power CT simulation unit is connected to the fifth end of the power module, the first end of the fourth power CT simulation unit is also connected to the sixth end of the power module, the first end of the fourth power CT simulation unit is also connected to the seventh end of the power module, the second end of the fifth circuit breaker is also connected to the first end of the seventh circuit breaker, the second end of the seventh circuit breaker is connected to the first end of the sixth power CT simulation unit, the second end of the sixth power CT simulation unit is connected to the eighth end of the power supply, the first end of the third circuit breaker is also connected to the first end of the eighth circuit breaker, and the second end of the eighth circuit breaker is connected to the first end of the sixth circuit breaker; The first end and the second end of the power module are used to provide a first primary current, the third end and the fourth end of the power module are used to provide a second primary current, the fifth end and the sixth end of the power module are used to provide a third primary current, and the seventh end and the eighth end of the power module are used to provide a fourth primary current; The first power CT simulation unit, the second power CT simulation unit, the third power CT simulation unit, the fourth power CT simulation unit, the fifth power CT simulation unit and the sixth power CT simulation unit all include a detection output end, and the detection output end is used to output the secondary current to the difference ratio module; The control module is also used to switch the on and off states of the first circuit breaker, the second circuit breaker, the third circuit breaker, the fourth circuit breaker, the fifth circuit breaker, the sixth circuit breaker, the seventh circuit breaker and the eighth circuit breaker respectively according to the test instruction to change the secondary current output by the first power CT simulation unit, the second power CT simulation unit, the third power CT simulation unit, the fourth power CT simulation unit, the fifth power CT simulation unit and the sixth power CT simulation unit.

10. The system according to claim 9, characterized in that The current transformer simulation module also includes a first standard CT comparison unit, a second standard CT comparison unit, a third standard CT comparison unit, a fourth standard CT comparison unit, a fifth standard CT comparison unit and a sixth standard CT comparison unit, wherein: The first end of the first standard CT comparison unit is connected to the second end of the first power CT simulation unit, the second end of the first standard CT comparison unit is connected to the first end of the first circuit breaker, the first end of the second standard CT comparison unit is connected to the second end of the second power CT simulation unit, the second end of the second standard CT comparison unit is connected to the second end of the power module, the first end of the third standard CT comparison unit is connected to the second end of the third power CT simulation unit, the second end of the third standard CT comparison unit is connected to the third end of the power module, the first end of the fourth standard CT comparison unit is connected to the second end of the fourth power CT simulation unit, the second end of the fourth standard CT comparison unit is connected to the first end of the fifth circuit breaker, the first end of the fifth standard CT comparison unit is connected to the second end of the fifth power CT simulation unit, the second end of the fifth standard CT comparison unit is connected to the fifth end of the power module, the first end of the sixth standard CT comparison unit is connected to the second end of the sixth power CT simulation unit, and the second end of the sixth standard CT comparison unit is connected to the eighth end of the power module.

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