CN220568861U - Insulation resistance testing device for actively inhibiting induced voltage - Google Patents

Abstract

The utility model discloses an insulation resistance testing device that always actively suppresses induced voltage. It includes an induced voltage monitoring and control module, a series resonance excitation voltage suppression module and a parallel resonance insulation resistance testing module. The utility model is based on the existing hybrid resonance network without Based on the source suppression induced voltage, it was improved to active suppression of induced voltage. A new type of active insulation resistance suppression induced voltage test was designed based on real-time monitoring of the frequency, phase, and amplitude of the induced voltage, and feedback control of active excitation to eliminate the induced voltage. system.

Description

An insulation resistance testing device that actively suppresses induced voltage

Technical field

The utility model relates to the technical field of high-voltage testing of electric power equipment, and specifically refers to an insulation resistance testing device that actively suppresses induced voltage.

Background technique

According to the requirements of preventive test procedures for power equipment, transformers, transformers, switches and other transformer equipment need to be inspected for insulation resistance, and the insulation resistance inspection used is one of the most effective methods to determine the insulation status of electrical equipment on site.

During the maintenance of substation equipment, preventive tests are often carried out to measure the insulation resistance of the maintenance equipment. The distance between the power outage equipment and adjacent live equipment is small, which causes the power outage maintenance equipment to easily generate induced voltage. It is easy to use conventional insulation resistance test instruments under the induced voltage. Damaged or unable to measure accurately.

The site needs an insulation resistance test device suitable for resisting induced voltage during the maintenance of substation equipment, which can be safe, reliable, convenient and fast to accurately measure the insulation resistance of maintenance equipment with induced voltage. At present, the passive resonant network method that has been developed does not remove the induced voltage, and there is a safety hazard of induced voltage injuring people.

Contents of the invention

The purpose of this utility model is to provide an insulation resistance testing device that actively suppresses induced voltage. Based on the existing passive suppression of induced voltage based on a hybrid resonant network, this utility model is improved to actively suppress induced voltage and is designed. A new device based on real-time monitoring of the frequency, phase, and amplitude of induced voltage and feedback control of active excitation to eliminate induced voltage.

In order to achieve this purpose, the utility model designs an insulation resistance test device that actively suppresses induced voltage, which is characterized in that: it includes an induced voltage monitoring and control module, a series resonance excitation voltage suppression module and a parallel resonance insulation resistance test module;

It includes an induced voltage monitoring and control module, a series resonance excitation voltage suppression module and a parallel resonance insulation resistance test module;

The series resonance excitation voltage suppression module includes a switch k1, a switch k3, a series capacitor C1, a resistor R1, a reactor L1 and an excitation power supply. The ground terminal of the excitation power supply is connected to the ground, and the output end of the excitation power supply is connected to one end of the reactor L1. The other end of the reactor L1 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to one end of the series capacitor C1, the other end of the series capacitor C1 is connected to one end of the switch k1, and the other end of the switch k1 is used to access the maintenance equipment casing to conduct electricity. The end of the rod Cx, one end of the switch k3 is used to access the end of the conductive rod Cx of the maintenance equipment casing;

The induced voltage monitoring and control module includes a voltage monitoring device, a voltage deviation control calculation device, a voltage excitation control device and a voltage dividing capacitor Cf. The reference voltage parameter monitoring end of the voltage monitoring device is used to access the power supply in the station. The monitoring result output end is connected to the signal input end of the voltage deviation control calculation device, the signal output end of the voltage deviation control calculation device is connected to the signal input end of the voltage excitation control device, and the control signal output end of the voltage excitation control device is connected to the excitation power control end. , the other end of the switch k3 is connected to one end of the voltage dividing capacitor Cf, and the other end of the voltage dividing capacitor Cf is connected to the induced voltage monitoring end of the voltage monitoring device;

The parallel resonance insulation resistance test module includes an insulation resistance test device, a parallel capacitor C2, a reactor L2, a resistor R2 and a switch k2. The negative pole of the insulation resistance test device is grounded, and the positive pole of the insulation resistance test device is connected to one end of the reactor L2. The positive electrode of the resistance testing device is also connected to one end of the parallel capacitor C2, the other end of the reactor L2 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to the other end of the parallel capacitor C2, the other end of the resistor R2 is connected to one end of the switch k2, and the switch The other end of k2 is used to connect to the Cx end of the conductive rod casing of the maintenance equipment.

Beneficial effects of this utility model:

This utility model monitors the waveform parameters of the frequency, phase, and amplitude of the induced voltage on the conductive rod Cx of the casing of the maintenance equipment, modulates the input reverse voltage waveform parameters of the excitation power supply, and acts through the series resonance system resistor R1, reactor L1, and series capacitor C1 On the conductive rod Cx of the casing of the maintenance equipment, the series resonance system conducts the AC voltage and blocks the DC voltage. When applying the DC test, it effectively ensures the isolation of DC voltage and reduces the induced voltage of the conductive rod Cx of the casing of the maintenance equipment to below 10V. Using The conventional insulation resistance testing device conducts the insulation resistance test on the conductive rod Cx of the maintenance equipment casing through the resistor R2, reactor L2, and parallel capacitor C2 of the parallel resonance system. The parallel resonance system conducts DC voltage and blocks AC voltage. During the insulation resistance test process It is guaranteed that the Cx induced voltage of the casing conductive rod of the maintenance equipment can be controlled in real time, and the DC voltage of the test device effectively acts on the tested product, effectively ensuring the safety of test personnel and equipment and the accuracy of insulation resistance testing.

Description of drawings

Figure 1 is a structural block diagram of the utility model;

Figure 2 is a schematic diagram of the maintenance equipment in the present utility model actively suppressing the induced voltage.

Among them, 1-voltage monitoring device, 2-voltage deviation control calculation device, 3-voltage excitation control device, 4-station power supply, 5-excitation power supply, 6-insulation resistance test device.

Detailed ways

The utility model will be further described in detail below in conjunction with the accompanying drawings and specific embodiments:

As shown in Figure 1, an insulation resistance test device that actively suppresses induced voltages includes an induced voltage monitoring and control module, a series resonance excitation voltage suppression module and a parallel resonance insulation resistance test module;

The series resonance excitation voltage suppression module includes a switch k1, a switch k3, a series capacitor C1, a resistor R1, a reactor L1 and an excitation power supply 5. The ground terminal of the excitation power supply 5 is connected to the ground, and the output end of the excitation power supply 5 is connected to the reactor L1. One end of the reactor L1 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to one end of the series capacitor C1, the other end of the series capacitor C1 is connected to one end of the switch k1, and the other end of the switch k1 is used to access maintenance equipment The Cx end of the casing conductive rod, one end of the switch k3 is used to access the Cx end of the casing conductive rod of the maintenance equipment;

The induced voltage monitoring and control module includes a voltage monitoring device 1, a voltage deviation control calculation device 2, a voltage excitation control device 3 and a voltage dividing capacitor Cf. The reference voltage parameter monitoring end of the voltage monitoring device 1 is used to access the power supply 4 in the station. , the monitoring result output end of the voltage monitoring device 1 is connected to the signal input end of the voltage deviation control calculation device 2, the signal output end of the voltage deviation control calculation device 2 is connected to the signal input end of the voltage excitation control device 3, and the control of the voltage excitation control device 3 The signal output end is connected to the control end of the excitation power supply 5, the other end of the switch k3 is connected to one end of the voltage dividing capacitor Cf, and the other end of the voltage dividing capacitor Cf is connected to the induced voltage monitoring end of the voltage monitoring device 1;

The parallel resonance insulation resistance test module includes an insulation resistance test device 6, a parallel capacitor C2, a reactor L2, a resistor R2 and a switch k2. The negative electrode of the insulation resistance test device 6 is connected to the ground, and the positive electrode of the insulation resistance test device 6 is connected to the reactor L2. At one end, the positive electrode of the insulation resistance testing device 6 is also connected to one end of the parallel capacitor C2, the other end of the reactor L2 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to the other end of the parallel capacitor C2, and the other end of the resistor R2 is connected to the switch k2 One end of the switch k2 and the other end of the switch k2 are used to connect to the end of the conductive rod Cx of the maintenance equipment casing, and the grounding end of the maintenance equipment Cx is grounded.

In the above technical solution, the maintenance equipment is various primary primary equipment in the substation such as transformers, circuit breakers, isolating switches, voltage transformers, current transformers or power cables.

In the above technical solution, the resonant frequency of the series resonance excitation voltage suppression module is 50Hz. The resonant frequency of the parallel resonant insulation resistance test module is 50Hz, and the resonant component parameters are adjusted according to the induced voltage frequency to maintain the consistency of the induced voltage and the resonant frequency. The excitation power supply 5 is an AC excitation power supply.

In the above technical solution, the induced voltage monitoring and control module monitors the real-time frequency, phase and amplitude of the induced voltage on the conductive rod Cx of the casing of the maintenance equipment, and calculates the induced voltage deviation by comparing it with the voltage frequency and phase of the power supply 4 in the station. According to The induced voltage deviation generates the control parameters of the reverse voltage excitation power supply, modulates the input voltage of the excitation power supply 5, and acts on the maintenance equipment Cx through the resistor R1, reactor L1 and series capacitor C1 of the series resonance system to reduce the induced voltage to below 10V. .

In the above technical solution, the AC excitation power acts on the maintenance equipment through a series resonance low impedance system, weakening the amplitude of the induced voltage.

In the above technical solution, the parameters of the series capacitor C1 in the series resonance excitation voltage suppression module are 20kV/100nF, which is high resistance, the parameters of the reactor L1 are 20kV/101.4H, and the parameters of the resistor R1 are 1kΩ. The series resonance excitation voltage suppression module The resonant frequency is 50Hz. Generally, the induced voltage of the maintenance equipment is a power frequency voltage. If it is a non-power frequency AC induced voltage, monitor the actual voltage frequency F of the maintenance equipment and replace the reactor L1 to make the series resonance system resistor R1, reactor L1 and series capacitor C1 The resonant frequency is F1. The station power is modulated to a voltage waveform with a frequency of F1 through a SPWM (sinusoidal pulse width modulation) transformer frequency converter to provide an input voltage waveform to the excitation power supply 5 .

In the above technical solution, when the amplitude of the induced voltage of the maintenance equipment drops below 10V, a conventional insulation resistance testing device 6 is used to test the insulation resistance of the maintenance equipment Cx through the resistor R2, reactor L2, and parallel capacitor C2 of the parallel resonance system; parallel resonance It has low DC resistance and high AC resistance, which enables the DC voltage output by the insulation resistance testing device to effectively act on the maintenance equipment, and suppresses the AC voltage from acting on the conventional insulation resistance testing device, protecting the safety of personnel and equipment, and reliably testing the insulation resistance of the maintenance equipment. .

In the above technical solution, the parameters of the parallel capacitor C2 in the parallel resonance insulation resistance test module are 20kV/32nF, the parameters of the reactor L2 are 20kV/316.9H, and the parameters of the resistor R2 are 1kΩ. The resonance of the parallel resonance insulation resistance test module The frequency is 50Hz. Generally, the induced voltage of maintenance equipment Cx is a power frequency voltage. If it is a non-power frequency AC induced voltage, monitor the actual voltage frequency F2 of the maintenance equipment and replace the reactor L2, so that the resistance R2, reactor L2, and parallel capacitor of the parallel resonance system can be adjusted. The resonant frequency of C2 is F2, which blocks AC voltage and protects the safety of test instruments and personnel.

In the above technical solution, the parameters of the voltage monitoring device 1 are voltage 0~100kV, frequency 20Hz~300Hz, phase 0~360°, the model of the voltage deviation control calculation device 2 is selected as WHNR-YYPC, and the model of the voltage excitation control device 3 is selected as WHNR -YYLC, the parameters of the excitation power supply 5 are voltage 0~100kV, frequency 20Hz~300Hz, and the model of the insulation resistance test device 6 is Fluke 1550C.

The working process of this utility model is:

First, hang the grounding rod at the conductive rod of the Cx casing of the maintenance equipment, and connect it to the test equipment according to the circuit shown in Figure 1. After initially turning off the switches k1, k2, and k3, remove the Cx grounding rod of the maintenance equipment.

First close the switch k3, and monitor the frequency, phase and amplitude of the induced voltage on the maintenance equipment through the voltage monitoring device 1. At the same time, the voltage monitoring device 1 obtains the frequency and phase data of the voltage of the power supply in the station, and calculates the maintenance equipment through the voltage deviation control calculation device. The phase and frequency deviation between the induced voltage and the power supply voltage waveform in the station is then modulated. The SPWM frequency conversion modulation method is used to output a voltage waveform with the same frequency and phase as the induced voltage of the maintenance equipment and the opposite amplitude, that is, the reverse applied excitation is obtained. According to the input voltage parameters of the power supply 5, close the switch k1, input voltage excitation to the excitation power supply 5 through the voltage excitation control device 3, and then monitor the waveform parameters of the induced voltage of the maintenance equipment in real time through the voltage monitoring device 1, and adjust the input control parameters of the excitation power supply in real time. , the goal is to make the amplitude of the induced voltage on the maintenance equipment <10V (see Figure 2 for the residual voltage of the maintenance equipment).

In Figure 1, at this moment, switches k1 and k3 are closed and k2 is open. The resistor R1, reactor L1 and series capacitor C1 of the series resonance system can pass the AC voltage and block the DC voltage. The series capacitor C1 has high insulation resistance and reduces leakage current to avoid affecting the accuracy of the insulation resistance test of subsequent maintenance equipment.

In the above system, reduce the induced voltage of the maintenance equipment to below 10V, close the switch k2, and use the conventional insulation resistance testing device 6 to conduct the insulation resistance test of the detection equipment through the resistor R2, reactor L2, and parallel capacitor C2 of the parallel resonance system. Parallel resonance The system's resistor R2, reactor L2, and parallel capacitor C2 can pass the DC voltage output by the insulation resistance testing device 6 and block the AC voltage that may be generated at k2 due to detuning from acting on the insulation resistance testing device 6. During the insulation resistance testing process It is guaranteed that the induced voltage of the maintenance equipment can be controlled in real time, and the DC voltage output by the insulation resistance testing device 6 can effectively act on the tested product, effectively ensuring the safety of test personnel and equipment and the accuracy of insulation resistance testing.

After the insulation resistance test is completed in the above process, the output DC voltage of the insulation resistance test device 6 is reduced to zero, and after the insulation resistance test device 6 is powered off, the switch k2 is turned off. At the end of the reactor L2, the insulation resistance test is The high-voltage side of the output of device 6 is discharged through the glow resistor to ground.

Then, the voltage excitation control device 3 controls the input voltage of the excitation power supply 5 to drop to zero, turn off the switch k1, and then turn off the switch k3. Hang a ground rod at the end of the conductive rod of the casing of the maintenance equipment Cx, and perform inspection on Cf and series capacitor C1 respectively. Discharge. Remove all wiring of the test equipment, and after full discharge, remove the grounding rod at the end of the conductive rod of the Cx casing of the maintenance equipment to complete the entire testing process.

Contents not described in detail in this specification belong to the prior art known to those skilled in the art.

Claims (5)

1. An insulation resistance test device that actively suppresses induced voltage, characterized in that: it includes an induced voltage monitoring and control module, a series resonance excitation voltage suppression module and a parallel resonance insulation resistance test module; The series resonance excitation voltage suppression module includes switch k1, switch k3, series capacitor C1, resistor R1, reactor L1 and excitation power supply (5), wherein the ground terminal of the excitation power supply (5) is grounded, and the excitation power supply (5) The output end is connected to one end of the reactor L1, the other end of the reactor L1 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to one end of the series capacitor C1, the other end of the series capacitor C1 is connected to one end of the switch k1, and the other end of the switch k1 It is used to connect to the end Cx of the conductive rod of the casing of the maintenance equipment. One end of the switch k3 is used to connect to the end Cx of the conductive rod of the casing of the maintenance equipment; The induced voltage monitoring and control module includes a voltage monitoring device (1), a voltage deviation control calculation device (2), a voltage excitation control device (3) and a voltage dividing capacitor Cf. The reference voltage parameter monitoring of the voltage monitoring device (1) The terminal is used to access the power supply (4) in the station, the monitoring result output terminal of the voltage monitoring device (1) is connected to the signal input terminal of the voltage deviation control calculation device (2), and the signal output terminal of the voltage deviation control calculation device (2) is connected to the voltage The signal input end of the excitation control device (3) and the control signal output end of the voltage excitation control device (3) are connected to the control end of the excitation power supply (5). The other end of the switch k3 is connected to one end of the voltage dividing capacitor Cf. The voltage dividing capacitor The other end of Cf is connected to the induced voltage monitoring end of the voltage monitoring device (1); The parallel resonant insulation resistance test module includes an insulation resistance test device (6), a parallel capacitor C2, a reactor L2, a resistor R2 and a switch k2. The negative electrode of the insulation resistance test device (6) is grounded, and the negative electrode of the insulation resistance test device (6) is grounded. The positive electrode is connected to one end of the reactor L2. The positive electrode of the insulation resistance testing device (6) is also connected to one end of the parallel capacitor C2. The other end of the reactor L2 is connected to one end of the resistor R2. The other end of the resistor R2 is connected to the other end of the parallel capacitor C2. The other end of the resistor R2 is connected to one end of the switch k2, and the other end of the switch k2 is used to connect to the end Cx of the conductive rod of the maintenance equipment casing. 2. The insulation resistance testing device for actively suppressing induced voltage according to claim 1, characterized in that the maintenance equipment is a transformer, a circuit breaker, an isolation switch, a voltage transformer, a current transformer or a power cable. 3. The insulation resistance testing device for actively suppressing induced voltage according to claim 1, characterized in that: the resonant frequency of the series resonance excitation voltage suppression module is 50 Hz. 4. The insulation resistance testing device for actively suppressing induced voltage according to claim 1, characterized in that: the resonant frequency of the parallel resonance insulation resistance testing module is 50 Hz. 5. The insulation resistance testing device for actively suppressing induced voltage according to claim 1, characterized in that: the excitation power supply (5) is an AC excitation power supply.