A voltage transformer secondary circuit wiring detection system and method

Abstract

The present invention provides a voltage transformer secondary circuit wiring detection system and method, the detection system includes a pressure module, a measurement module and a calculation and analysis module, the pressure module and the measurement module are connected to the three-phase output port of the voltage transformer, and the calculation and analysis module is connected to the measurement module. The detection method specifically measures the voltage of the damping winding of the voltage transformer first and determines whether the polarity series connection of the damping winding is wrong. If an error occurs, the detection is stopped and an alarm is issued. If the series connection is correct, the voltage and phase at both ends of each corresponding secondary circuit of the voltage transformer are measured and the voltage transformer ratio and polarity are calculated. Finally, according to the accuracy of the voltage transformer polarity and ratio, it is determined whether the secondary circuit wiring is correct. If it is accurate, the secondary circuit wiring is correct. If it is wrong, the secondary circuit wiring is wrong. The present invention eliminates the complicated operation process and can greatly improve the detection efficiency of the voltage transformer secondary circuit wiring.

Description

Technical Field

[0001] The present invention relates to the field of power equipment detection, and in particular to a voltage transformer secondary circuit wiring detection system and method. Background Art

[0002] In the 10kV neutral ungrounded system, the bus voltage transformer has generally adopted the four-voltage transformer wiring method in recent years. The characteristic of the four-voltage transformer wiring method is that the three-phase voltage transformer is connected in a star shape and grounded after the zero-sequence voltage transformer is connected in series, which can effectively suppress the ferromagnetic resonance of the neutral point ungrounded system. However, due to the large number of secondary terminals of the four-voltage transformer, it is easy to have a secondary circuit wiring error. In the existing methods for checking the secondary circuit of the four-voltage transformer, most of them use a voltage regulator to pressurize the voltage transformer on the primary side, and use a multimeter to measure the voltage on the secondary winding, and calculate the transformation ratio and polarity to judge the accuracy of the secondary circuit wiring. However, most of these methods lack a dedicated pressure device. If a single-phase voltage regulator is used, it is difficult to judge whether the polarity of the detuning winding is accurate. If a three-phase voltage regulator is used, it is difficult to ensure the output three-phase balance due to its large size and weight, which will affect the final test results. In addition, during the inspection process, the process of dismantling and restoring the wiring is relatively complicated, and it is easy to make mistakes. Most existing detection methods use manual data recording, but during the inspection process, the voltage measurement is many times and takes a long time, which puts a heavy burden on the test personnel. In addition, the large amount of complex data will make it difficult to judge the test results. In addition, since the existing single-phase voltage regulator and three-phase voltage regulator are not electrically isolated, the zero-sequence voltage transformer grounding terminal needs to be disassembled before the test voltage is applied, which is a complicated operation. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a voltage transformer secondary circuit wiring verification system and method.

[0004] The purpose of the present invention is achieved through the following technical solutions:

[0005] A voltage transformer secondary circuit wiring detection system includes a voltage transformer, a pressure module, a measuring module and a calculation and analysis module, wherein the pressure module and the measuring module are both connected to the three-phase output port of the voltage transformer, the calculation and analysis module is connected to the measuring module, the pressure module is used to pressure the three-phase output port of the voltage transformer, the measuring module is used to measure the secondary circuit related voltage of the voltage transformer, and the calculation and analysis module is used to analyze whether the secondary circuit wiring of the voltage transformer is correct according to the voltage measured by the measuring module.

[0006] Furthermore, the boosting module includes a rectifier unit, a three-phase inverter and a chopper circuit, wherein the rectifier unit is used to convert the input AC voltage into a DC voltage, the three-phase inverter is used to convert the DC voltage output by the rectifier unit into an AC voltage, and the chopper circuit is used to regulate the AC voltage converted by the three-phase inverter.

[0007] Furthermore, a three-phase step-up isolation transformer is provided between the three-phase inverter and the chopper circuit, and the three-phase step-up isolation transformer is used to electrically isolate the power input and the voltage output.

[0008] Furthermore, a voltage transformer secondary circuit wiring detection system also includes a display module and a storage module, the display module is connected to the measurement module, and the display module is also connected to the calculation and analysis module, the display module is used to display measurement data and detection results, the storage module is connected to the measurement module and the calculation and analysis module at the same time, the storage module is used to store measurement data and detection result data, and the storage module also includes a USB interface, and the USB interface is used to output the data stored in the storage module.

[0009] Furthermore, the measurement module includes a voltage sampling circuit, which includes a sampling chip U1, a voltage reference circuit and a plurality of decoupling capacitors. The output port of the voltage reference circuit is connected to the REF pin of the sampling chip U1, and the voltage reference circuit is used to provide a reference voltage for the voltage conversion of the sampling chip U1; the REFCAPA pin, REFCAPB pin, REFCAPC pin, all AVCC pins, DVCC pin, VDRIVE pin, VDD and VSS pins of the sampling chip U1 are all connected to decoupling capacitors.

[0010] Furthermore, the voltage reference circuit includes an electrolytic capacitor C1, a capacitor C2 and a resistor R1, the positive electrode of the electrolytic capacitor C1 is connected to the REF pin of the sampling chip U1, the negative electrode of the electrolytic capacitor C1 is grounded, one end of the resistor R1 is connected to the SEL REF pin of the sampling chip U1, and the other end of the resistor R1 is connected to a +3.3V voltage source.

[0011] A method for detecting connection of a secondary circuit of a voltage transformer comprises the following steps:

[0012] Step 1: Switch the measurement channel of the voltage transformer secondary circuit wiring detection system to the damping winding channel, and connect the measurement module to the voltage transformer;

[0013] Step 2: The measuring module measures the voltage of the damping winding of the voltage transformer, and the calculation and analysis module determines whether there is an error in the polarity series connection of the damping winding according to the voltage value of the damping winding. If the voltage value of the damping winding exceeds the preset voltage threshold, there is an error in the polarity series connection of the damping winding, and an alarm is issued and the detection is stopped. If the voltage value of the damping winding does not exceed the preset voltage threshold, the series connection is correct, and step 3 is executed;

[0014] Step 3: Switch the damping winding channel to the secondary measurement channel, measure the voltage and phase at both ends of each corresponding voltage transformer secondary circuit of the voltage transformer, and the calculation and analysis module calculates the voltage transformer ratio and polarity according to the measured voltage and phase;

[0015] Step 4: The calculation and analysis module determines whether the polarity and ratio are accurate based on the voltage transformer ratio and polarity calculation results. If accurate, it determines that the voltage transformer secondary circuit wiring is correct. If wrong, it determines that the voltage transformer secondary circuit wiring is wrong and issues an alarm.

[0016] Furthermore, when judging the damping winding polarity series connection error in step 2, the primary side of the voltage transformer is also pressurized. The pressurization of the primary side of the voltage transformer is specifically to apply a three-phase balanced voltage to the A phase, B phase and C phase of the primary side of the voltage transformer.

[0017] Furthermore, in step three, when measuring the voltage and phase at both ends of the secondary circuit of the voltage transformer, the pressure module performs unidirectional pressure processing on phase A, phase B and phase C of the primary side of the voltage transformer respectively, and the measurement module obtains the voltage and phase at both ends of the secondary circuit corresponding to each phase after pressure is applied.

[0018] Furthermore, in step 4, the specific steps of judging whether the polarity and ratio of the secondary circuit are accurate according to the calculation results of the polarity and ratio of the voltage transformer are as follows: obtaining the standard ratio k of the voltage transformer detuning winding, applying single-phase voltage to the primary side A phase of the voltage transformer, and applying a voltage of U A , the voltage U between the secondary side A630 and N600 AN , the voltage U across the secondary side A630 to L630 an And the corresponding secondary side L630 to N630 voltage U nN1 ;

[0019] Single-phase voltage is applied to the primary side B phase of the voltage transformer, and the applied voltage is U B , the voltage U between the secondary side B630 and N600 BN , the voltage U between the secondary side B630 and L630 bn And the corresponding secondary side L630 to N630 voltage U nN2 ;

[0020] Single-phase voltage is applied to the primary side C phase of the voltage transformer, and the applied voltage is U C , the voltage U between the secondary side C630 and N600 CN , the voltage U between the secondary side C630 and L630 cn And the corresponding secondary side L630 to N630 voltage U nN3 ;

[0021] when In the case of , it is judged that the transformation ratio and polarity of the secondary circuit are correct; in other cases, it is judged that the transformation ratio and polarity of the secondary circuit are wrong.

[0022] The beneficial effects of the present invention are:

[0023] The pressurization requirement during the detection process is achieved through the pressurization module, which can be used for both single-phase and three-phase pressurization. While ensuring that the detection system is easy to operate and carry, it can also ensure that the three-phase imbalance rate of the output three-phase balanced voltage will not affect the judgment of the detection result. In addition, the three-phase step-up isolation transformer is used to achieve electrical isolation, and there is no need to perform additional disassembly of the zero-sequence voltage transformer grounding terminal operation, which reduces the difficulty of operation and ensures the safety of the detection process. The display module intuitively displays the measurement data and test results, and there is no need to manually record the measurement data, which improves the measurement efficiency while ensuring accuracy. The stored measurement data and test result data can be output and called for subsequent reference. Compared with the traditional voltage transformer secondary circuit wiring verification method, it can save the complicated operation process, the test results are accurate and intuitive, and the detection efficiency of the voltage transformer secondary circuit wiring is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of the present invention;

[0025] Figure 2 is a schematic diagram of a pressurizing module of the present invention;

[0026] Figure 3 is a schematic diagram of a voltage sampling circuit according to an embodiment of the present invention;

[0027] Figure 4 It is a schematic diagram of a process of the present invention;

[0028] Among them: 1. pressurization module, 11. rectifier unit, 12. three-phase inverter, 13. chopper circuit, 14. three-phase step-up isolation transformer, 2. measurement module, 3. calculation and analysis module, 4. display module, 5. storage module, 6. voltage transformer. DETAILED DESCRIPTION

[0029] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0030] Example:

[0031] A voltage transformer secondary circuit wiring detection system, such as Figure 1 As shown, it includes a voltage transformer 6, a pressurizing module 1, a measuring module 2, a calculation and analysis module 3, a display module 4 and a storage module 5. The pressurizing module 1 and the measuring module 2 are both connected to the three-phase output port of the voltage transformer 6, the calculation and analysis module 3 is connected to the measuring module 2, the pressurizing module 1 is used to pressurize the three-phase output port of the voltage transformer 6, the measuring module 2 is used to measure the secondary circuit related voltage of the voltage transformer 6, and the calculation and analysis module 3 is used to analyze whether the secondary circuit wiring of the voltage transformer is correct according to the voltage measured by the measuring module 2.

[0032] The display module 4 is connected to the measurement module 2, and the display module 4 is also connected to the calculation and analysis module 3. The display module 4 is used to display the measurement data and the test results. The storage module 5 is connected to the measurement module 2 and the calculation and analysis module 3 at the same time. The storage module 5 is used to store the measurement data and the test result data. The storage module 5 also includes a USB interface, and the USB interface is used to output the data stored in the storage module 5.

[0033] By integrating three-phase pressurization and single-phase pressurization, there is no need to pressurize separately, which reduces the difficulty of operation. The data measured by the measurement module 2 is directly calculated and analyzed, and there is no need to manually record all the data and calculate them. The measured data is used to automatically determine whether the secondary circuit wiring of the voltage transformer is accurate, thereby improving the detection efficiency and reducing the calculation error rate.

[0034] The amount of data generated during the detection of the secondary circuit of the voltage transformer is large, and manual recording is bound to result in data recording errors, and it is not convenient to search for data later. Displaying the measurement results and the detection results through the display module 4 can effectively improve the accuracy of data recording and ensure the accuracy of subsequent detection results. The storage module 5 also includes a USB interface, which can be used to export data, making it convenient to record and view data.

[0035] like Figure 2 As shown, the boosting module 1 includes a rectifier unit 11, a three-phase inverter 12 and a chopper circuit 13. A three-phase step-up isolation transformer 14 is also provided between the three-phase inverter 12 and the chopper circuit 13. The rectifier unit 11 is used to convert the input AC voltage into a DC voltage. The three-phase inverter 12 is used to convert the DC voltage output by the rectifier unit 11 into an AC voltage. The chopper circuit 13 is used to regulate the AC voltage converted by the three-phase converter. The three-phase step-up isolation transformer 14 is used to electrically isolate the power input and the voltage output.

[0036] The boost voltage is controlled by the chopper circuit 13 , and different boost requirements can be met by adjusting the chopper circuit 13 , thus being adaptable to more application scenarios.

[0037] In the traditional secondary circuit detection process, due to the lack of electrical isolation, the zero-sequence voltage transformer grounding terminal needs to be disconnected, and the operation during the detection process is very complicated. Electrical isolation through the three-phase step-up isolation transformer 14 can effectively reduce the difficulty of the detection process while ensuring safety.

[0038] The measuring module 2 includes a voltage sampling circuit, such as Figure 3 As shown, the voltage sampling circuit includes a sampling chip U1, a voltage reference circuit and 9 decoupling capacitors. The sampling chip U1 uses a sampling chip of model AD7656. The output port of the voltage reference circuit is connected to the REF pin of the sampling chip U1. The voltage reference circuit is used to provide a reference voltage for the voltage conversion of the sampling chip U1. The REFCAPA pin, REFCAPB pin, REFCAPC pin, all AVCC pins, DVCC pin, VDRIVE pin, VDD and VSS pins of the sampling chip U1 are all connected with decoupling capacitors. In order to ensure the normal operation of the sampling chip U1, the sampling chip U1 The pin is also connected to a +5V voltage source through resistor R2. All AGND pins of the sampling chip U1 are connected in parallel and connected to the analog ground, while all DGND pins of the sampling chip U1 are connected in parallel and connected to the digital ground. The VSS pin of the sampling chip U1 is also connected to a -12V voltage source. The above decoupling capacitors are all an electrolytic capacitor and a capacitor in parallel.

[0039] The voltage reference circuit includes an electrolytic capacitor C1, a capacitor C2 and a resistor R1. The positive electrode of the electrolytic capacitor C1 is connected to the REF pin of the sampling chip U1, the negative electrode of the electrolytic capacitor C1 is grounded, one end of the resistor R1 is connected to the SEL REF pin of the sampling chip U1, and the other end of the resistor R1 is connected to a +3.3V voltage source.

[0040] The voltage data related to the secondary circuit of the voltage transformer is collected through the voltage sampling circuit, and the reference voltage is provided through the voltage reference circuit in the voltage sampling circuit. The reference voltage is used as a measurement reference to ensure the measurement accuracy of the voltage sampling circuit.

[0041] A voltage transformer secondary circuit wiring detection method, such as Figure 4 As shown, the following steps are included:

[0042] Step 1: Switch the measurement channel of the voltage transformer secondary circuit wiring detection system to the damping winding channel, and connect the measurement module 2 to the voltage transformer 6;

[0043] Step 2: The measuring module 2 measures the voltage of the damping winding of the voltage transformer 6. The calculating and analyzing module 3 determines whether there is an error in the polarity series connection of the damping winding according to the voltage value of the damping winding. If the voltage value of the damping winding exceeds the preset voltage threshold, there is an error in the polarity series connection of the damping winding, and an alarm is issued and the detection is stopped. If the voltage value of the damping winding does not exceed the preset voltage threshold, the series connection is correct, and step 3 is executed;

[0044] Step 3: Switch the damping winding channel to the secondary measurement channel, measure the voltage and phase at both ends of each corresponding voltage transformer secondary circuit of the voltage transformer 6, and the calculation and analysis module 3 calculates the transformation ratio and polarity of the voltage transformer 6 according to the measured voltage and phase;

[0045] Step 4: The calculation and analysis module 3 determines whether the polarity and ratio are accurate based on the calculation results of the voltage transformer 6 ratio and polarity. If accurate, it is determined that the secondary circuit wiring of the voltage transformer is correct. If wrong, it is determined that the secondary circuit wiring of the voltage transformer is wrong and an alarm is issued.

[0046] First, the polarity of the damping winding of the secondary circuit of the voltage transformer is judged in series. If the polarity of the damping winding is connected in series incorrectly, the data collected by the subsequent measurement module 2 will be wrong, and if there is a directional relay protection, it will cause the relay protection to malfunction. The transformation ratio and polarity of the voltage transformer 6 can check whether the number of winding turns, lead wires and tap lead wires are connected accurately. The polarity and transformation ratio of the voltage transformer 6 are obtained by measuring the obtained voltage and phase, thereby realizing the wiring detection of the secondary circuit of the voltage transformer.

[0047] When judging the polarity series connection error of the damping winding in step 2, the primary side of the voltage transformer 6 is also pressurized. The pressurization of the primary side of the voltage transformer 6 is specifically to apply a three-phase balanced voltage to the A phase, B phase and C phase of the primary side of the voltage transformer 6.

[0048] When the polarity of the damping winding is connected in series incorrectly, if single-phase voltage is applied, it is difficult to determine whether the polarity of the damping winding is correct from the voltage data measured later. After applying the three-phase balanced voltage, due to the magnetic field generated by the applied voltage, if the polarity of the damping winding is connected in series correctly, the two voltage values ​​between one phase and the other two phases should be basically the same. If the voltage difference between the two voltages exceeds the preset threshold, it can be determined that the polarity of the damping winding is connected incorrectly.

[0049] In step three, when measuring the voltage and phase at both ends of the secondary circuit of the voltage transformer, the pressure module 1 performs unidirectional pressure treatment on the primary side A phase, B phase and C phase of the voltage transformer 6 respectively, and the measurement module 2 obtains the voltage and phase at both ends of the secondary circuit corresponding to each phase after pressure is applied.

[0050] In step 4, the specific steps of judging whether the polarity and transformation ratio of the secondary circuit are accurate according to the calculation results of the polarity and transformation ratio of the voltage transformer 6 are as follows: obtaining the standard transformation ratio k of the detuning winding of the voltage transformer 6, where Single-phase voltage is applied to the primary side A phase of voltage transformer 6, and the applied voltage is U A , the voltage U between the secondary side A630 and N600 AN , the voltage U across the secondary side A630 to L630 an And the corresponding secondary side L630 to N630 voltage U nN1 ;

[0051] Single-phase voltage is applied to the primary side B phase of voltage transformer 6, and the applied voltage is U B , the voltage U between the secondary side B630 and N600 BN , the voltage U between the secondary side B630 and L630 bn And the corresponding secondary side L630 to N630 voltage U nN2 ;

[0052] Single-phase voltage is applied to the primary side C phase of voltage transformer 6, and the applied voltage is U C , the voltage U between the secondary side C630 and N600 CN , the voltage U between the secondary side C630 and L630 cn And the corresponding secondary side L630 to N630 voltage U nN3 ;

[0053] when In the case of , it is judged that the transformation ratio and polarity of the secondary circuit are correct; in other cases, it is judged that the transformation ratio and polarity of the secondary circuit are wrong.

[0054] Once the equation of one phase does not hold, it can be determined that the polarity of the detuning winding is reversed, and the phase whose equation does not hold is the phase whose polarity is reversed.

[0055] By calculating and analyzing the transformation ratio and polarity of the secondary circuit, the wiring of the secondary circuit can be judged. If the transformation ratio and polarity are accurate, the wiring of the secondary circuit is accurate. If the transformation ratio and polarity are wrong, the wiring of the secondary circuit is wrong. During the operation, there is no need to disassemble the transformer terminals and grounding terminals except the detuning winding, and the accuracy of the test results can also be guaranteed.

[0056] The above-described embodiment is only a preferred solution of the present invention and does not limit the present invention in any form. There are other variations and modifications without exceeding the technical solution described in the claims.

Claims

1. A voltage transformer secondary circuit wiring detection system, characterized in that: It includes a voltage transformer, a pressure module, a measuring module and a calculation and analysis module, wherein the pressure module and the measuring module are both connected to the three-phase output port of the voltage transformer, the calculation and analysis module is connected to the measuring module, the pressure module is used to perform pressure treatment on the three-phase output port of the voltage transformer, the measuring module is used to measure the secondary circuit related voltage of the voltage transformer, and the calculation and analysis module is used to analyze whether the secondary circuit wiring of the voltage transformer is correct according to the voltage measured by the measuring module; The pressure module includes a rectifier unit, a three-phase inverter and a chopper circuit, wherein the rectifier unit is used to convert the input AC voltage into a DC voltage, the three-phase inverter is used to convert the DC voltage output by the rectifier unit into an AC voltage, and the chopper circuit is used to perform voltage regulation on the AC voltage converted by the three-phase inverter; A voltage transformer secondary circuit wiring detection method applicable to a voltage transformer secondary circuit wiring detection system comprises the following steps: Step 1: Switch the measurement channel of the voltage transformer secondary circuit wiring detection system to the damping winding channel, and connect the measurement module to the voltage transformer; Step 2: The measuring module measures the voltage of the damping winding of the voltage transformer, and the calculation and analysis module determines whether there is an error in the polarity series connection of the damping winding according to the voltage value of the damping winding. If the voltage value of the damping winding exceeds the preset voltage threshold, there is an error in the polarity series connection of the damping winding, and an alarm is issued and the detection is stopped. If the voltage value of the damping winding does not exceed the preset voltage threshold, the series connection is correct, and step 3 is executed; Step 3: Switch the damping winding channel to the secondary measurement channel, measure the voltage and phase at both ends of each corresponding voltage transformer secondary circuit of the voltage transformer, and the calculation and analysis module calculates the voltage transformer ratio and polarity according to the measured voltage and phase; Step 4: The calculation and analysis module determines whether the secondary circuit polarity and transformation ratio are accurate based on the calculation results of the voltage transformer polarity and transformation ratio. If accurate, it determines that the secondary circuit wiring of the voltage transformer is correct. If wrong, it determines that the secondary circuit wiring of the voltage transformer is wrong and issues an alarm.

2. A voltage transformer secondary circuit wiring detection system according to claim 1, characterized in that: A three-phase step-up isolation transformer is also provided between the three-phase inverter and the chopper circuit, and the three-phase step-up isolation transformer is used for electrically isolating the power input and the voltage output.

3. A voltage transformer secondary circuit wiring detection system according to claim 1, characterized in that: It also includes a display module and a storage module. The display module is connected to the measurement module, and the display module is also connected to the calculation and analysis module. The display module is used to display measurement data and test results. The storage module is connected to the measurement module and the calculation and analysis module at the same time. The storage module is used to store measurement data and test result data. The storage module also includes a USB interface, and the USB interface is used to output the data stored in the storage module.

4. A voltage transformer secondary circuit wiring detection system according to claim 1, characterized in that: The measurement module includes a voltage sampling circuit, which includes a sampling chip U1, a voltage reference circuit and a plurality of decoupling capacitors. The output port of the voltage reference circuit is connected to the REF pin of the sampling chip U1, and the voltage reference circuit is used to provide a reference voltage for the voltage conversion of the sampling chip U1; the REFCAPA pin, REFCAPB pin, REFCAPC pin, all AVCC pins, DVCC pin, VDRIVE pin, VDD and VSS pins of the sampling chip U1 are all connected with decoupling capacitors.

5. A voltage transformer secondary circuit wiring detection system according to claim 4, characterized in that: The voltage reference circuit includes an electrolytic capacitor C1, a capacitor C2 and a resistor R1. The positive electrode of the electrolytic capacitor C1 is connected to the REF pin of the sampling chip U1, the negative electrode of the electrolytic capacitor C1 is grounded, one end of the resistor R1 is connected to the SELREF pin of the sampling chip U1, and the other end of the resistor R1 is connected to a +3.3V voltage source.

6. A voltage transformer secondary circuit wiring detection method, characterized in that: The following steps are involved: Step 1: Switch the measurement channel of the voltage transformer secondary circuit wiring detection system to the damping winding channel, and connect the measurement module to the voltage transformer; Step 2: The measuring module measures the voltage of the damping winding of the voltage transformer, and the calculation and analysis module determines whether there is an error in the polarity series connection of the damping winding according to the voltage value of the damping winding. If the voltage value of the damping winding exceeds the preset voltage threshold, there is an error in the polarity series connection of the damping winding, and an alarm is issued and the detection is stopped. If the voltage value of the damping winding does not exceed the preset voltage threshold, the series connection is correct, and step 3 is executed; Step 3: Switch the damping winding channel to the secondary measurement channel, measure the voltage and phase at both ends of each corresponding voltage transformer secondary circuit of the voltage transformer, and the calculation and analysis module calculates the voltage transformer ratio and polarity according to the measured voltage and phase; Step 4: The calculation and analysis module determines whether the secondary circuit polarity and transformation ratio are accurate based on the calculation results of the voltage transformer polarity and transformation ratio. If accurate, it determines that the secondary circuit wiring of the voltage transformer is correct. If wrong, it determines that the secondary circuit wiring of the voltage transformer is wrong and issues an alarm.

7. A voltage transformer secondary circuit wiring detection method according to claim 6, characterized in that: When judging the polarity series connection error of the damping winding in step 2, the primary side of the voltage transformer is also pressurized. The pressurization of the primary side of the voltage transformer is specifically to apply a three-phase balanced voltage to the A phase, B phase and C phase of the primary side of the voltage transformer.

8. A voltage transformer secondary circuit wiring detection method according to claim 6, characterized in that: In step three, when measuring the voltage and phase at both ends of the secondary circuit of the voltage transformer, the pressure module performs unidirectional pressure treatment on the A phase, B phase and C phase of the primary side of the voltage transformer respectively, and the measurement module obtains the voltage and phase at both ends of the secondary circuit corresponding to each phase after pressure is applied.

9. A voltage transformer secondary circuit wiring detection method according to claim 6, characterized in that: In step 4, the specific steps of judging whether the polarity and ratio of the secondary circuit are accurate according to the calculation results of the polarity and ratio of the voltage transformer are as follows: obtaining the standard ratio k of the voltage transformer detuning winding, applying single-phase voltage to the primary side A phase of the voltage transformer, and applying a voltage of U A , the voltage U between the secondary side A630 and N600 AN , the voltage U across the secondary side A630 to L630 an And the corresponding secondary side L630 to N630 voltage U nN1 ; Single-phase voltage is applied to the primary side B phase of the voltage transformer, and the applied voltage is U B , the voltage U between the secondary side B630 and N600 BN , the voltage U between the secondary side B630 and L630 bn And the corresponding secondary side L630 to N630 voltage U nN2 ; Single-phase voltage is applied to the primary side C phase of the voltage transformer, and the applied voltage is U C , the voltage U between the secondary side C630 and N600 CN , the voltage U between the secondary side C630 and L630 cn And the corresponding secondary side L630 to N630 voltage U nN3 ; when When the secondary circuit ratio and polarity are correct, In other cases, errors occur in judging the transformation ratio and polarity of the secondary circuit.

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