Performance test system of voltage transformer on-line monitoring device

Abstract

The invention relates to a performance test system of a voltage transformer on-line monitoring device. The system comprises a power supply module, a capacitance voltage division module, a difference value proportion module and a control module, wherein the power supply module is used for providing primary voltage; the capacitance voltage dividing module is used for obtaining secondary voltage based on the primary voltage and simulating a voltage transformer; 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 voltage to obtain a test signal, and inputting the test signal to the voltage transformer online monitoring device; and the control module is also used for obtaining an output result of the voltage transformer online monitoring device after obtaining the test signal, and obtaining a performance test result of the voltage transformer online monitoring device according to the output result and the differential signal. By adopting the method, the accuracy of the performance test of the online monitoring device of the voltage transformer can be improved.

Description

Technical Field

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

[0002] A power voltage transformer is a special transformer that converts a high-voltage signal into a low-voltage signal in proportion and transmits it to a secondary-side electric energy metering device, measuring instrument, relay protection, and automatic device. It is a connection component between the primary system and the secondary system. On-site verification of it is the basis for ensuring the safe and stable operation of the power grid and the fair trading of electricity resources. As a key metering instrument in the power system, it is 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 the fair trading of electricity, etc. Therefore, on-line monitoring of the voltage transformer to determine whether the operating state of the device is accurate is of great significance for the normal operation of the voltage transformer, and further determines the reliability of the power grid power supply and the accuracy of the electric energy metering device. At present, those skilled in the art usually monitor the state of the voltage transformer through an on-line monitoring device of the voltage transformer to achieve functions such as error monitoring, state evaluation, and operation and maintenance management of the voltage transformer.

[0003] In the actual application of the voltage transformer monitoring device, the monitoring device needs to be calibrated before installation to ensure its normal metering and correct analysis and evaluation; with factors such as the service life of the device and the influence of the external environment, the accuracy of the on-line monitoring device of the voltage transformer may be affected. Therefore, there is an urgent need for a performance test system for the on-line monitoring device of the voltage transformer to test the monitoring accuracy of the on-line monitoring device of the voltage transformer. Summary of the Invention

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

[0005] This application provides a performance test system for an on-line monitoring device of a voltage transformer, including a power supply module, a capacitive voltage division module, a differential ratio module, and a control module, wherein:

[0006] The power supply module is used to provide a primary voltage for the capacitive voltage division module;

[0007] The capacitive voltage division module is used to obtain a secondary voltage based on the primary voltage to simulate a voltage transformer;

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

[0009] The differential ratio module is configured to generate a differential signal based on the voltage amplitude parameter and the voltage phase parameter, superimpose the differential signal on the secondary voltage to obtain a test signal for the on-line monitoring device of the voltage transformer, and input the test signal into the on-line monitoring device of the voltage transformer;

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

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

[0012] The regulated power supply unit is configured to generate three-phase voltages and provide them as primary voltages to the capacitive voltage division module;

[0013] The control module is further configured to adjust the three-phase voltages according to the test instruction, so that the output frequency of the three-phase voltages is 50 Hz or 60 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.

[0014] In one embodiment, the capacitive voltage division module includes an upper-bridge-arm capacitor and a lower-bridge-arm capacitor;

[0015] The first end of the upper-bridge-arm capacitor is connected to the output end of the power supply module for receiving the primary voltage; the second end of the upper-bridge-arm capacitor is connected to the first end of the lower-bridge-arm capacitor, the second end of the lower-bridge-arm capacitor is connected to the neutral end of the power supply module, the second end of the upper-bridge-arm capacitor is further connected to the first input end of the differential ratio module, and the second end of the lower-bridge-arm capacitor is further connected to the second input end of the differential ratio module;

[0016] The lower-bridge-arm capacitor is used to divide the voltage to obtain the secondary voltage, and the differential ratio module receives the secondary voltage through the first input end and the second input end.

[0017] In one embodiment, the capacitive voltage division module includes an upper-bridge-arm capacitor and a lower-bridge-arm capacitor;

[0018] The first end of the upper-bridge-arm capacitor is connected to the output end of the power supply module for receiving the primary voltage; the second end of the upper-bridge-arm capacitor is connected to the first end of the lower-bridge-arm capacitor, the second end of the lower-bridge-arm capacitor is connected to the first current signal test end of the on-line voltage transformer monitoring device, the second current signal test end of the on-line voltage transformer monitoring device is connected to the neutral end of the power supply module, the second end of the upper-bridge-arm capacitor is further connected to the first input end of the difference ratio module, and the second end of the lower-bridge-arm capacitor is further connected to the second input end of the difference ratio module;

[0019] The lower-bridge-arm capacitor is used for dividing the primary voltage to obtain the secondary voltage, and the difference ratio module receives the secondary voltage through the first input end and the second input end;

[0020] The on-line voltage transformer monitoring device obtains the current output by the lower-bridge-arm capacitor under the secondary voltage through the first current signal test end and the second current signal test end, and performs primary current measurement.

[0021] In one embodiment, the voltage ratio of the capacitive voltage division module is 220 / 57.7.

[0022] In one embodiment, the upper-bridge-arm capacitor and the lower-bridge-arm capacitor have the same temperature coefficient.

[0023] In one embodiment, the upper-bridge-arm capacitor and the lower-bridge-arm capacitor are encapsulated and arranged in an oil-immersed structure.

[0024] In one embodiment, the total capacitance configuration range of the capacitive voltage division module is 3 uF to 7 uF.

[0025] In one embodiment, the difference ratio module includes a frequency-stabilized and voltage-stabilized power supply unit, a programmed voltage regulation unit, a signal synthesis unit, and a signal superposition unit; wherein,

[0026] The input end of the frequency-stabilized and voltage-stabilized power supply unit is connected to the commercial power, and is used for outputting a voltage signal that matches both the voltage amplitude parameter and the voltage phase parameter according to the voltage amplitude parameter and the voltage phase parameter;

[0027] The programmed voltage regulation unit is used for obtaining an in-phase component and a quadrature component based on the voltage signal;

[0028] The signal synthesis unit is used for synthesizing the in-phase component and the quadrature component to obtain a differential signal;

[0029] The signal superposition unit is used for superposing the differential signal and the secondary voltage.

[0030] In one embodiment, the signal superposition unit is an isolation transformer, and the isolation transformer is used to superpose the differential signal and the secondary voltage.

[0031] The performance test system of the above voltage transformer on-line monitoring device simulates the secondary voltage output by the voltage transformer through the capacitive voltage division module, generates a differential signal through the differential ratio module, and superposes the secondary voltage and the differential signal through the differential ratio module, that is, constructs a voltage transformer model with variable error state through the capacitive voltage division module and the differential ratio module, so as to perform performance tests on the voltage transformer on-line monitoring device through test signals representing different error states, and can accurately evaluate the monitoring performance of the voltage sensor on-line monitoring device under different working conditions. In addition, the differential ratio module can generate a differential signal containing accurate voltage amplitude and voltage phase, which can improve the accuracy and reliability of the performance test. Description of the Drawings

[0032] 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 use in 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, other related drawings can be obtained based on these drawings without creative efforts.

[0033] Figure 1 It is a structural block diagram of a performance test system of a voltage transformer on-line monitoring device in one embodiment;

[0034] Figure 2 It is a first schematic structural diagram of the capacitive voltage division module in the performance test system of the voltage transformer on-line monitoring device in one embodiment;

[0035] Figure 3 It is a second schematic structural diagram of the capacitive voltage division module in the performance test system of the voltage transformer on-line monitoring device in one embodiment;

[0036] Figure 4 It is a first schematic structural diagram of the differential ratio module in the performance test system of the voltage transformer on-line monitoring device in one embodiment;

[0037] Figure 5 It is a schematic structural diagram of a simulation type test platform of the voltage transformer on-line monitoring device in another embodiment;

[0038] Figure 6 It is a schematic structural diagram of the capacitive voltage division unit in the simulation type test platform of the voltage transformer on-line monitoring device in another embodiment;

[0039] Figure 7 It is a schematic structural diagram of the difference ratio unit in the simulation type test platform of the on-line monitoring device for voltage transformers in another embodiment. Detailed implementation manners

[0040] In order to make the objectives, technical solutions and advantages of the present application clearer and more understandable, the present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0041] It should be noted that when an element is considered to be "connected" to another element, it may be directly connected to the other element and integrated with it, or there may be an intermediate element at the same time. The terms "disconnected", "one end", "the other end" and similar expressions used herein are only for the purpose of illustration.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present application belongs. The terms used herein in the description of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0043] 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 the features. In the description of the present application, if the term "a plurality" appears, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0044] In the present application, unless otherwise clearly specified and limited, if terms such as "installation", "connection", "connection", "fixation", etc. appear, these terms should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may 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 the present application can be understood according to specific circumstances.

[0045] In order to be able to test the performance of the on-line monitoring device for voltage transformers to test the monitoring accuracy of the on-line monitoring device for voltage transformers, an embodiment of the present application provides a performance test system for the on-line monitoring device for voltage transformers, as Figure 1As shown in the figure, the above system includes a power supply module 110, a capacitive voltage division module 120, a difference ratio module 130, and a control module 140, where:

[0046] The above power supply module 110 is used to provide a primary voltage for the above capacitive voltage division module 120.

[0047] Among them, the power supply module can be an adjustable AC power supply, capable of generating a primary voltage signal with a preset amplitude and frequency. The primary voltage can refer to the voltage on the input side of the voltage transformer, which is an untransformed voltage, usually a high voltage. That is to say, the primary voltage is the original signal to be measured by the voltage transformer. In this embodiment, the primary voltage can refer to the voltage input from the power supply module to the capacitive voltage division module.

[0048] The above capacitive voltage division module 120 is used to obtain a secondary voltage based on the above primary voltage for simulating a voltage transformer.

[0049] Among them, the capacitive voltage division module is used to simulate the behavior of the voltage transformer. It can detect the primary voltage (high voltage) on the input side and output a corresponding secondary voltage (low voltage) to realize the reproduction of the voltage transformer function. The capacitive voltage division module is used to obtain a secondary voltage based on the above primary voltage, which can mean that after receiving the primary voltage, the capacitive voltage division module can perform processing and conversion to obtain the secondary voltage. A voltage transformer is an electrical device used to measure AC voltage, capable of converting a high voltage signal into a smaller, proportional voltage signal for easy measurement and monitoring. The capacitive voltage division module provides a real input signal for subsequent tests by simulating the working state of the voltage transformer in actual applications.

[0050] The above control module 140 is used to send micro-difference signal generation parameters to the above difference ratio module 130 according to a test instruction; the micro-difference signal generation parameters include a voltage amplitude parameter and a voltage phase parameter.

[0051] Among them, the micro-difference signal generation parameters are used to indicate the generation of a micro-difference signal. The control module 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. The control module executes according to the test instructions included in the above program, and the control module sends the micro-difference signal generation parameters obtained during the program execution to the difference ratio module. Both the preset error scheme and the custom error scheme can be used to preset the error of the analog voltage transformer, and this error can be used for the online monitoring error assessment of the voltage transformer on-line monitoring device to be tested. The micro-difference signal generation parameters can include a voltage amplitude parameter and a voltage phase parameter, and these parameters are used to comprehensively simulate the signal characteristics of the output of the voltage transformer and are an important basis for test signal generation.

[0052] The above-mentioned differential ratio module 130 is used to generate a differential signal according to the above-mentioned voltage amplitude parameter and the above-mentioned voltage phase parameter, and superimpose the differential signal on the above-mentioned secondary voltage to obtain a test signal for the on-line monitoring device of the voltage transformer, and input the test signal into the on-line monitoring device of the voltage transformer.

[0053] Among them, the differential signal can refer to a voltage signal with a very small voltage, and these signals are used to simulate small-amplitude change signals or fault characteristic signals that may occur in the actual operation of the voltage transformer. In this embodiment, the differential signal can refer to a voltage signal generated by the differential ratio module according to the voltage amplitude parameter and the above-mentioned voltage phase parameter. This voltage signal is used to be superimposed on the secondary voltage output by the capacitive voltage division module to obtain a test signal for performing performance testing on the on-line monitoring device of the voltage transformer, and then input this test signal into the on-line monitoring device of the voltage transformer. The test signal is used to simulate the error voltage signals that may occur in different voltage transformers in the actual scenario, so as to evaluate the monitoring performance of the on-line monitoring device of the voltage transformer. In addition, the voltage amplitude parameter and the voltage phase parameter used to generate the differential signal can be used to calculate the ratio error and the phase error. Both the ratio error and the phase error are important indicators describing the performance of the voltage transformer. Therefore, the accuracy of the voltage transformer monitoring can be determined through the differential signal.

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

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

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

[0057] 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 on-line monitoring device of the voltage transformer.

[0058] In the implementation manner of the present application, the on-line monitoring device of the voltage transformer is the device to be tested. For any existing on-line monitoring device of the voltage transformer, the present application only needs to determine its monitoring error (monitoring performance) according to the data (output result) it displays, without considering how it realizes error monitoring.

[0059] Exemplarily, the control module controls the power supply module to turn on. The power supply module provides a stable high voltage as the primary voltage to the capacitive voltage division module. The capacitive voltage division module receives the primary voltage of the high voltage, reduces the primary voltage to the secondary voltage through the internal capacitor configuration, and inputs the secondary voltage to the differential ratio module, which can simulate the function of the voltage transformer to output the secondary voltage after receiving the primary voltage. The control module obtains the differential signal generation parameters including the voltage amplitude parameter and the voltage phase parameter according to the received test instruction, and sends them to the differential ratio module. The differential ratio module generates the corresponding differential signal according to the voltage amplitude parameter and the above voltage phase parameter. The differential ratio module can superimpose the generated differential signal and the secondary voltage output by the capacitive voltage division module through the adder circuit to obtain the test signal for the on-line monitoring device of the voltage transformer. The differential ratio module inputs the test signal into the on-line monitoring device of the voltage transformer to be tested. The on-line monitoring device of the voltage transformer processes the test signal to obtain the output result. After the on-line monitoring device of the voltage transformer receives the test signal, the control module obtains the output result of the device, and comprehensively analyzes the output result and the differential signal to obtain the performance test result of the on-line monitoring device of the voltage transformer.

[0060] For the performance test system of the above on-line monitoring device of the voltage transformer, the capacitive voltage division module is used to simulate the output of the secondary voltage of the voltage transformer, the differential ratio module is used to generate the differential signal, and the differential ratio module superimposes the secondary voltage and the differential signal, that is, a voltage transformer model with variable error state is constructed by the capacitive voltage division module and the differential ratio module. Thus, the performance of the on-line monitoring device of the voltage transformer is tested by the test signals representing different error states, and the monitoring performance of the voltage sensor on-line monitoring device under different working conditions can be accurately evaluated. In addition, the differential ratio module can generate the differential signal including the accurate voltage amplitude and voltage phase, which can improve the accuracy and reliability of the performance test.

[0061] In an exemplary embodiment, the above power supply module includes a regulated power supply unit; the regulated power supply unit is used to generate three-phase voltage and provide it to the capacitive voltage division module as the primary voltage; the control module is further used to adjust the three-phase voltage according to the above test instruction, so that the output frequency of the three-phase voltage is 50 Hz or 60 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.

[0062] Among them, the regulated power supply unit can refer to a power supply device that provides stable voltage and current output. In this embodiment, it can be used to provide stable and reliable three-phase voltage to the capacitive voltage division module.

[0063] Exemplarily, the regulated power supply unit can receive an external power input (such as mains power and industrial power, etc.), and through the internal voltage regulation circuit and adjustment mechanism, generate a stable and adjustable three-phase AC voltage. The regulated power supply unit can include components such as a transformer, a rectifier, a filter, and a voltage regulator, etc., to ensure the stability and accuracy of the output voltage; the control module can, according to the test instructions characterizing the test requirements, instruct the regulated power supply unit to adjust the three-phase voltage so that the output frequency of the above three-phase voltage is 50 Hz or 60 Hz, the output voltage adjustment range is from 0 V to 250 V, and the three-phase phase adjustment range is from 0 degrees to 180 degrees; the regulated power supply unit provides the adjusted three-phase voltage as the primary voltage to the capacitive voltage division module.

[0064] In this embodiment, by providing a stable three-phase voltage through the regulated power supply unit and being able to adjust the output frequency of the three-phase voltage, the output voltage adjustment range, and the three-phase phase adjustment range according to the test requirements, the reliability and flexibility of the test can be improved.

[0065] In an exemplary embodiment, as Figure 2 shown, the above capacitive voltage division module includes an upper bridge arm capacitor 201 and a lower bridge arm capacitor 202;

[0066] The first end of the above upper bridge arm capacitor 201 is connected to the output end of the above power supply module for receiving the above primary voltage; the second end of the above upper bridge arm capacitor 201 is connected to the first end of the above lower bridge arm capacitor 202, the second end of the above lower bridge arm capacitor 202 is connected to the neutral end of the above power supply module, the second end of the above upper bridge arm capacitor 201 is also connected to the first input end of the above difference ratio module, and the second end of the above lower bridge arm capacitor 202 is also connected to the second input end of the above difference ratio module.

[0067] The above lower bridge arm capacitor 202 is used to divide the voltage to obtain the above secondary voltage, and the above difference ratio module receives the above secondary voltage through the above first input end and the above second input end.

[0068] Among them, in the capacitive voltage division module, that is, in the circuit inside the capacitive voltage division module as Figure 2 shown, the upper bridge arm capacitor 201 is a capacitor close to the power output end, and together with the lower bridge arm capacitor, forms a voltage division circuit; the lower bridge arm capacitor 202 in the capacitive voltage division module is a capacitor located at the power neutral end (such as the port N as Figure 2 shown), and together with the upper bridge arm capacitor, generates a secondary voltage with a voltage value lower than that of the primary voltage through voltage division, and outputs the secondary voltage to the first input end and the second input end of the difference ratio module through the lines at both ends of the lower bridge arm capacitor 202.

[0069] Among them, the upper-bridge-arm capacitor receives the input primary voltage, which can ensure a stable and low-impedance connection for the lower-bridge-arm capacitor to reduce signal interference. Then, through the connection of the neutral terminal, a complete current loop is formed, enabling the upper-bridge-arm capacitor and the lower-bridge-arm capacitor to operate normally.

[0070] In this embodiment, through the upper-bridge-arm capacitor and the lower-bridge-arm capacitor in the capacitive voltage division module, the high-voltage primary voltage can be converted into a secondary voltage suitable for testing to simulate the function of a voltage transformer. This structure of the bridge-arm capacitor can simplify the circuit layout and reduce the testing cost.

[0071] In an exemplary embodiment, as Figure 3 shown, the above capacitive voltage division module includes an upper-bridge-arm capacitor 301 and a lower-bridge-arm capacitor 302;

[0072] The first end of the above upper-bridge-arm capacitor 301 is connected to the output end of the above power supply module for receiving the above primary voltage; the second end of the above upper-bridge-arm capacitor 301 is connected to the first end of the above lower-bridge-arm capacitor 302, the second end of the above lower-bridge-arm capacitor 302 is connected to the first current signal test end of the above on-line monitoring device for voltage transformer, the second current signal test end of the above on-line monitoring device for voltage transformer is connected to the neutral terminal of the above power supply module (such as Figure 3 the port N shown), the second end of the above upper-bridge-arm capacitor 301 is also connected to the first input end of the above difference ratio module, and the second end of the above lower-bridge-arm capacitor 302 is also connected to the second input end of the above difference ratio module;

[0073] The above lower-bridge-arm capacitor 302 is used to divide the above primary voltage to obtain the above secondary voltage, and the above difference ratio module receives the above secondary voltage through the above first input end and the above second input end;

[0074] The above on-line monitoring device for voltage transformer obtains the current output by the above lower-bridge-arm capacitor 302 under the above secondary voltage through the above first current signal test end and the above second current signal test end, and performs a primary current measurement.

[0075] Among them, in the capacitive voltage division module, that is, in the circuit inside the capacitive voltage division module as Figure 3 shown, the upper-bridge-arm capacitor 301 is a capacitor close to the power supply output end, and together with the lower-bridge-arm capacitor, it forms a voltage division circuit; the lower-bridge-arm capacitor 302 in the capacitive voltage division module is a capacitor close to the power supply neutral terminal, and together with the upper-bridge-arm capacitor, it generates a secondary voltage with a voltage value lower than that of the primary voltage through voltage division, and outputs the secondary voltage to the first input end and the second input end of the difference ratio module through the lines at both ends of the lower-bridge-arm capacitor 302.

[0076] Among them, the upper-bridge-arm capacitor receives the input primary voltage, which can ensure the stable and low-impedance connection of the lower-bridge-arm capacitor to reduce signal interference. Then, through the first current signal test terminal and the second current signal test terminal of the voltage transformer on-line monitoring device, the connection to the neutral terminal of the power supply module forms a complete current loop, enabling the upper-bridge-arm capacitor and the lower-bridge-arm capacitor to work properly. That is, as Figure 3 shown, the wire end 303 is connected to the first current signal test terminal of the voltage transformer on-line monitoring device, and the wire end 304 is connected to the second current signal test terminal of the voltage transformer on-line monitoring device. That is, the voltage transformer on-line monitoring device can obtain the current output by the lower-bridge-arm capacitor under the above secondary voltage through the above first current signal test terminal and the above second current signal test terminal, and can measure the primary current. The measured primary current is both the current corresponding to the upper-bridge-arm capacitor and the current corresponding to the lower-bridge-arm capacitor, which can be regarded as the current formed by the self-capacitance reactance of the upper-bridge-arm capacitor under the corresponding voltage division, or the current formed by the self-capacitance reactance of the lower-bridge-arm capacitor under the corresponding voltage division.

[0077] In this embodiment, through the upper-bridge-arm capacitor and the lower-bridge-arm capacitor in the capacitive voltage division module, the high-voltage primary voltage can be converted into a secondary voltage suitable for testing. By connecting the current signal input terminal of the voltage transformer on-line monitoring device between the lower-bridge-arm capacitor and the power supply neutral terminal, the function of the capacitive voltage transformer can be more realistically simulated to achieve the performance test of the voltage transformer on-line monitoring device including the secondary voltage test function and the primary current test function. By using the capacitive voltage division module with the above simple bridge-arm capacitor structure to simulate the capacitive voltage transformer, the comprehensive performance test of the voltage transformer on-line monitoring device can be realized, and the overall test cost can be reduced.

[0078] In an exemplary embodiment, the voltage ratio of the above capacitive voltage division module is 220 / 57.7. Among them, by setting the voltage ratio of the capacitive voltage division module to 220 / 57.7, the performance of the on-site operating power voltage transformer can be more realistically simulated.

[0079] In an exemplary embodiment, the temperature coefficients of the above upper-bridge-arm capacitor and the above lower-bridge-arm capacitor are the same. Among them, by ensuring that the capacitor materials and processes of the upper-bridge-arm capacitor and the above lower-bridge-arm capacitor are the same, the performance of the two capacitors can be guaranteed to be the same, achieving the purpose of the same temperature coefficient.

[0080] In an exemplary embodiment, the above upper-bridge-arm capacitor and the above lower-bridge-arm capacitor are encapsulated in an oil-immersed structure. Among them, by encapsulating the upper-bridge-arm capacitor and the above lower-bridge-arm capacitor in the capacitive voltage division module in an oil-immersed structure, the working environment of the on-site operating power voltage transformer can be more closely approximated, thereby improving the simulation authenticity of the test process.

[0081] In an exemplary embodiment, the total capacitance of the above capacitive voltage division module is configured in the range of 3 uF to 7 uF. Among them, configuring the total capacitance of the capacitive voltage division module in the range of 3 uF to 7 uF can make the primary current be 0.2 A to 0.5 A when the rated input voltage of the capacitive voltage division module is 220 V, so as to achieve the effect of being basically consistent with the primary current of the actually operating power capacitive voltage transformer, thereby improving the true reliability of the test.

[0082] In an exemplary embodiment, as Figure 4 shown, the above difference ratio module includes a frequency-stabilized and voltage-stabilized power supply unit 410, a programmable voltage regulation unit 420, a signal synthesis unit 430, and a signal superposition unit 440; among them, the input end of the above frequency-stabilized and voltage-stabilized power supply unit 410 is connected to the commercial power, and is used to output a voltage signal that matches both the above voltage amplitude parameter and the above voltage phase parameter according to the above voltage amplitude parameter and the above voltage phase parameter.

[0083] Among them, the input end of the frequency-stabilized and voltage-stabilized power supply unit is connected to the commercial power. For example, the frequency-stabilized and voltage-stabilized power supply unit can receive the input of commercial power 220V / 50Hz; the frequency-stabilized and voltage-stabilized power supply unit can monitor the amplitude and phase of the input voltage, adjust the power supply output according to the above voltage amplitude parameter and the above voltage phase parameter, realize the precise control of the voltage, output a voltage signal that matches both the above voltage amplitude parameter and the above voltage phase parameter, and this voltage signal has the characteristics of stable frequency and stable voltage.

[0084] The above programmable voltage regulation unit 420 is used to obtain the in-phase component and the quadrature component based on the above voltage signal.

[0085] Among them, the programmable voltage regulation unit can adopt digital signal processing technology to decompose the input voltage signal into an in-phase component and a quadrature component through a phase shift operation, that is, obtain the in-phase component and the quadrature component.

[0086] The above signal synthesis unit 430 is used to synthesize the above in-phase component and the above quadrature component to obtain a differential signal.

[0087] Among them, the signal synthesis unit can add the in-phase component and the quadrature component through an adder circuit to generate a combined signal as the differential signal, and the original voltage signal is finely adjusted in the process of generating the differential signal.

[0088] The above signal superposition unit 440 is used to superpose the above differential signal and the above secondary voltage.

[0089] Among them, the signal superposition unit can add the differential signal to the secondary voltage from the capacitive voltage division module through a superposition circuit to achieve the final adjustment of the secondary voltage, and at the same time output the final test signal.

[0090] In this embodiment, the frequency-stabilized and voltage-stabilized power supply unit in the difference ratio module can ensure the stability of the output signal under fluctuating mains conditions. By decomposing the voltage signal through the programmable voltage regulation unit and then synthesizing the signal through the signal synthesis unit, the original voltage signal can be finely adjusted to obtain a high-precision differential signal. Finally, the test signal is synthesized through the signal superposition unit, improving the accuracy and reliability of the test signal generation.

[0091] In an exemplary embodiment, the above signal superposition unit is an isolation transformer, and the isolation transformer is used to superimpose the above differential signal and the above secondary voltage.

[0092] Among them, the coil configuration inside the isolation transformer enables electromagnetic coupling between the primary coil (input differential signal) and the secondary coil (input secondary voltage signal). Through electromagnetic coupling, the signals of the two can be effectively superimposed. During the superimposition process, the isolation transformer only transmits the change of the differential signal to the secondary voltage signal, thereby forming a synthesized signal. The synthesized signal contains the characteristics of the original secondary voltage and the differential signal. The isolation transformer can provide electrical isolation to protect the equipment between the input end and the output end, avoid the conduction of electrical faults or short-circuit faults caused by signals with different potentials, and ensure the safety of operators.

[0093] In this embodiment, using the isolation transformer as the signal superposition unit can achieve the efficient synthesis of the differential signal and the secondary voltage on the premise of ensuring electrical safety, and improve the safety and stability of the performance test system.

[0094] In an exemplary embodiment, as Figure 5 shown, the present application also provides an emulation type test platform for an on-line monitoring device of a voltage transformer, including a voltage-stabilized power supply unit 510, a capacitive voltage division unit 520, a difference ratio unit 530, and a control unit 540. This test platform is used for voltage data acquisition and display inspection, current data acquisition and display inspection, channel relative error test, and evaluation of error characteristics of the on-line monitoring device for the error characteristics of the voltage transformer.

[0095] Among them, the channel relative error refers to the accuracy and relative error of the voltage signal measurement of the online monitoring device channels and between channels, which can be understood as the input standard signal (known signal) of the channel and the measurement accuracy of the test channel; (since the error of the tested voltage transformer is 0.2 level, the channel measurement accuracy needs to be at least 0.05 level to correctly identify the signal change); the error characteristic refers to the error change amount of the voltage transformer. Assuming that the errors of 12 voltage transformers are all qualified, the online monitoring device should be able to identify that the error of the currently monitored voltage transformer is qualified. Assuming that one of them is adjusted to be out of tolerance, the online monitoring device should be able to identify the out-of-tolerance and the position of the out-of-tolerance voltage transformer.

[0096] Among them, the output of the regulated power supply unit is 2 groups of three-phase voltage sources (as Figure 5 shown, one group of three-phase voltage output terminals are 1A, 1B, 1C, and the other group of three-phase voltage output terminals are 2A, 2B, 2C, and N is the power neutral terminal), the output frequency is 45Hz - 65Hz, which is convenient for simulating the primary input voltage of 50Hz and 60Hz voltage transformers; the output voltage is 0 - 250V, and the adjustment fineness is 0.1V; the three-phase phase adjustment range is 0° - 180°, and the adjustment fineness is 0.02°; the three-phase power stability is 0.05% / 2min; the above regulated power supply unit is used to output voltage to simulate the primary voltage of the voltage transformer and serve as the input source of the capacitive voltage division unit.

[0097] Among them, as Figure 6 shown, the capacitive voltage division unit consists of an upper bridge arm capacitor 601 and a lower bridge arm capacitor 602. The two capacitor materials and processes are the same to ensure their consistent performance (such as the temperature coefficient); the capacitive voltage division unit is encapsulated in an oil-immersed structure, which is closer to the working environment of the on-site operating power voltage transformer; the voltage ratio of the capacitive voltage division unit is 220V / 57.7V, which is used to simulate the voltage transformer, and the output voltage is also the same as the secondary voltage of the voltage transformer, which is 100 / √3V, the same as the secondary voltage of the voltage transformer and the rated input voltage of the voltage transformer online monitoring device; the voltage division ratio of the upper bridge arm capacitor and the lower bridge arm capacitor is 220V / (100 / √3V); the total capacitance of the capacitive voltage division unit is designed to be 3uF - 7uF. When the rated input voltage is 220V, the primary current is 0.2A - 0.5A, which is basically the same as the primary current of the power capacitive voltage transformer, and can be used for the current measurement of the voltage transformer online monitoring device with the primary current test function. Figure 6The figure shows the schematic diagram of the principle of primary current measurement of an on-line monitoring device for voltage transformers in a simulation-type test platform, which has the function of measuring the primary current of a power capacitive voltage transformer. Since the voltage output of the platform is obtained by voltage division of the capacitive voltage division unit, the primary capacitance of the capacitive voltage division unit is selected within the range of 3 μF - 7 μF. Under the rated primary voltage of 220V / 50Hz, its primary current range is within 0.2A - 0.5A. Its voltage and current values are basically the same as the secondary voltage and primary current of power capacitive voltage transformers (such as 110kV 10000pF, 220kV 5000pF), which can more realistically simulate the principle of capacitive voltage transformers and can better conduct simulation tests for some on-line monitoring devices of voltage transformers for secondary voltage and primary current tests. If the on-line monitoring device of the voltage transformer does not have the function of primary current measurement, the current signal terminals can be short-circuited.

[0098] Among them, the difference ratio unit superimposes the input signals of 12 capacitive voltage division units (such as Figure 5 the input shown) and 12 differential signals through the isolation unit. The differential signals can achieve programmed output of amplitude and phase. The difference ratio unit can be used to adjust the voltage amplitude and phase of the outputs of 12 capacitive voltage division units (such as Figure 5 the output shown). Figure 7 The figure shows the schematic diagram of the single-channel working principle of the difference ratio unit of a simulation-type test platform for an on-line monitoring device of a voltage transformer. Its principle is to superimpose the input signal from the capacitive voltage division unit (that is, Figure 7 the output of the capacitive voltage division unit shown in the figure, transmitted through lines a and n, where n is the line connected to the neutral terminal of the power supply and a is the line connected to the capacitive voltage division unit) with the differential signal through the isolation unit (such as an isolation transformer, etc.), so as to change the amplitude and phase of the input signal from the capacitive voltage division unit, achieving the purpose of changing the errors of 12 capacitive voltage division units. The differential signal output of the difference ratio unit is based on a frequency-stabilized and voltage-stabilized power supply and a programmed voltage regulating power supply as the voltage amplitude and phase reference, and then realizes the output of the in-phase component (ratio) and the quadrature component (phase), and achieves the precise output of the differential signal through signal synthesis. Among them, the isolation unit uses an isolation transformer for isolation, and superimposes the output voltage of the capacitive voltage division unit and the differential signal of the difference ratio unit through the isolation transformer. Because the two voltage signals have different relative potential points, they cannot be directly superimposed, otherwise it will cause a short circuit. Therefore, they can be superimposed after being isolated by the isolation transformer.

[0099] 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; to adjust and output the 12 micro differential signals of the differential ratio unit; and to cooperate with the management control program to implement the control of the preset scheme and the custom scheme. Among them, the control unit is also equipped with supporting software for setting the preset test scheme and the custom scheme, executing by the program control unit, collecting the detection results, evaluating the detection results, and outputting the reports.

[0100] In this embodiment, a device that can adjust the output ratio and phase difference, composed of 12 capacitor voltage division units and 12 differential ratio units, simulates the working state of the power voltage transformer. Among them, the capacitor voltage division unit is used to simulate the capacitor voltage transformer (CVT, Capacitor Voltage Transformers) used in the power system. Here, the capacitor voltage division unit has errors, but this error can be adjusted to within 0.2 levels during design, and it can more realistically simulate the CVT (the error level of the CVT is 0.2 levels). The 2 groups of outputs of the regulated power supply unit are used to simulate the primary power outputs of different voltage levels. The control unit is used to preset the errors of the 12 simulated voltage transformers 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 voltage transformer to be tested. Among them, the function of the on-line monitoring device is error evaluation, that is, the error change amount. Based on the known or qualified initial error, it monitors whether the subsequent error change amount exceeds the tolerance. The above scheme can measure and know the initial true value of the error of the capacitor voltage division unit, and can also know the error change amount through adjustment, so as to test whether the on-line monitoring device can correctly evaluate. The above scheme makes full use of the characteristics of the capacitor voltage division unit and the differential ratio unit to form a power voltage transformer model with adjustable errors. It can not only output voltage but also monitor its primary current, corresponding to the characteristics of the power electromagnetic voltage transformer and the power capacitor voltage transformer respectively. By adjusting the primary voltage characteristics and changing the errors of each simulated power voltage transformer through the control unit, the error characteristics evaluation of the on-line monitoring device for the error characteristics of the voltage transformer can be conveniently and quickly realized. Through the above-mentioned simulation test platform for the on-line monitoring device of the voltage transformer, the calibration of the on-line monitoring device of the voltage transformer can be realized truly and objectively, providing a high-reliability quantitative assessment and status evaluation of the metering performance for the voltage transformer after being put into operation, effectively improving the digital management level of the metering transformer, and ensuring the fairness and accuracy of the electric energy trade.

[0101] 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 as within the scope recorded in this application.

[0102] 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 an online monitoring device of a voltage transformer, characterized in that: The system includes a power supply module, a capacitor voltage division module, a difference ratio module and a control module, wherein: The power supply module is used to provide a primary voltage to the capacitor voltage dividing module; The capacitor voltage dividing module is used to obtain a secondary voltage based on the primary voltage, so as to simulate a voltage 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 voltage amplitude parameter and a voltage phase parameter; The difference ratio module is used to generate a differential signal according to the voltage amplitude parameter and the voltage phase parameter, and superimpose the differential signal with the secondary voltage to obtain a test signal for the voltage transformer online monitoring device, and input the test signal to the voltage transformer online monitoring device; The control module is also used to obtain the output result of the voltage transformer online monitoring device after obtaining the test signal, and obtain the performance test result of the voltage transformer online monitoring device according to the output result and the differential signal.

2. The system according to claim 1, characterized in that The power module includes a voltage-stabilized power supply unit; The voltage-stabilized power supply unit is used to generate a three-phase voltage and provide it as a primary voltage to the capacitor voltage-dividing module; The control module is also used to adjust the three-phase voltage according to the test instruction so that the output frequency of the three-phase voltage is 50Hz or 60Hz, the output voltage adjustment range is 0V to 250V, and the three-phase phase adjustment range is 0 degree to 180 degrees.

3. The system according to claim 1, characterized in that The capacitor voltage divider module includes an upper bridge arm capacitor and a lower bridge arm capacitor; The first end of the upper bridge arm capacitor is connected to the output end of the power module for receiving the primary voltage; the second end of the upper bridge arm capacitor is connected to the first end of the lower bridge arm capacitor, the second end of the lower bridge arm capacitor is connected to the neutral end of the power module, the second end of the upper bridge arm capacitor is also connected to the first input end of the difference ratio module, and the second end of the lower bridge arm capacitor is also connected to the second input end of the difference ratio module; The lower bridge arm capacitor is used for voltage division to obtain the secondary voltage, and the difference ratio module receives the secondary voltage through the first input terminal and the second input terminal.

4. The system according to claim 1, characterized in that The capacitor voltage divider module includes an upper bridge arm capacitor and a lower bridge arm capacitor; The first end of the upper bridge arm capacitor is connected to the output end of the power module for receiving the primary voltage; the second end of the upper bridge arm capacitor is connected to the first end of the lower bridge arm capacitor, the second end of the lower bridge arm capacitor is connected to the first current signal test end of the voltage transformer online monitoring device, the second current signal test end of the voltage transformer online monitoring device is connected to the neutral end of the power module, the second end of the upper bridge arm capacitor is also connected to the first input end of the difference ratio module, and the second end of the lower bridge arm capacitor is also connected to the second input end of the difference ratio module; The lower bridge arm capacitor is used to divide the primary voltage to obtain the secondary voltage, and the difference ratio module receives the secondary voltage through the first input terminal and the second input terminal; The voltage transformer online monitoring device obtains the current output by the lower bridge arm capacitor under the secondary voltage through the first current signal test terminal and the second current signal test terminal, and performs a primary current measurement.

5. The system according to claim 3 or 4, characterized in that: The voltage ratio of the capacitor voltage divider module is 220 / 57.

7.

6. The system according to claim 3 or 4, characterized in that: The temperature coefficients of the upper bridge arm capacitor and the lower bridge arm capacitor are the same.

7. The system according to claim 3 or 4, characterized in that: The upper bridge arm capacitor and the lower bridge arm capacitor are packaged and arranged in an oil-immersed structure.

8. The system according to claim 3 or 4, characterized in that: The overall capacitance configuration range of the capacitor voltage divider module is 3uF to 7uF.

9. The system according to claim 1, characterized in that The difference ratio module includes a frequency-stabilized voltage-stabilized power supply unit, a program-controlled voltage regulation unit, a signal synthesis unit, and a signal superposition unit; wherein, The input end of the frequency-stabilized voltage power supply unit is connected to the mains, and is used to output a voltage signal that matches the voltage amplitude parameter and the voltage phase parameter according to the voltage amplitude parameter and the voltage phase parameter; The program-controlled voltage regulating unit is used to obtain an in-phase component and a quadrature component based on the voltage signal; The signal synthesis unit is used to synthesize the in-phase component and the orthogonal component to obtain a differential signal; The signal superposition unit is used to superimpose the differential signal with the secondary voltage.

10. The system according to claim 9, characterized in that The signal superposition unit is an isolation transformer, and the isolation transformer is used to superimpose the differential signal with the secondary voltage.

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