A high-voltage capacitor voltage transformer transient response test system

Abstract

The utility model relates to a kind of high voltage capacitor voltage transformer transient response test system, including voltage regulating unit, output end and high voltage vacuum switch, the capacitor of being tested capacitor voltage transformer, reference voltage transformer connection;High voltage vacuum switch control loop, including closing button, and multiple branches connected with it;The multiple branches are located in high voltage vacuum switch, and the one end of the closing button and multiple branches connection is as control end and phase selector connection;Electronic measuring equipment, with reference voltage transformer secondary side terminal, the secondary side current transformer of being tested capacitor voltage transformer, being tested secondary side terminal connection.The utility model can complete the existing international general two kinds of frequency 50Hz and 60Hz voltage transformer transient response test, facilitate voltage transformer secondary terminal measurement wiring, make transient response test process simplify, improve overall test safety factor, guarantee personnel safety, improve transient response test efficiency.

Description

Technical Field

[0001] This utility model belongs to the field of instrument transformer manufacturing and relates to a transient response test system for high-voltage capacitive voltage transformers. Specifically, it is a transient response test system for simplifying the overall test process of voltage transformer products with a voltage level of 40.5kV or above. Background Technology

[0002] Currently, for voltage transformers with voltage levels of 40.5kV-1000kV and above, the minimum safe distance is approximately 1m, and the maximum safe distance is approximately 8.7m. This is because high-voltage transformers are excessively tall, heavy, and have high voltage levels. Existing test circuits have the following shortcomings:

[0003] The relay protection of the power grid needs to constantly reflect changes in the primary voltage through voltage transformers. When a short circuit to ground occurs in the power grid, the primary voltage drops to zero, and it is desirable for the secondary voltage to also drop to zero quickly. For capacitive voltage transformers (CVTs), since capacitors, reactors, and intermediate transformers are all energy storage components, this energy is released through the R, L, C circuits of the intermediate transformer and load, resulting in damped oscillations and causing excessively high residual voltage on the secondary side. It takes a period of time for the voltage to decay to zero. Therefore, transient response testing is an important type test item to verify whether the product can decay to less than 10% of the peak voltage before the short circuit within one cycle after a high-voltage short circuit, and to accurately transmit voltage signals to measuring instruments, meters, and relay protection devices. The existing test circuit mainly includes oscilloscopes and high-voltage vacuum switches. Because we did not have power phase selectors in the early stages, it was very difficult to find the peak value and zero crossing during the short circuit. Generally, it takes at least two to three attempts to succeed, resulting in low testing efficiency. Repeated tests over a long period of time not only damage the product, but also the high-voltage vacuum switch and oscilloscope, shortening the service life of the equipment. During the monitoring and testing process, manual operation could not accurately capture the correct waveform. After long-term use, some wiring of the circuit breaker showed signs of damage, and the rectifier block controlling the energy storage motor frequently burned out. Utility Model Content

[0004] In view of the above-mentioned shortcomings in the transient response test process of capacitive voltage transformers in the existing technology, the technical problem to be solved by this utility model is to provide a capacitive voltage transformer transient response test system that improves test efficiency, has high safety and reliability, is easy to operate, and eliminates safety hazards.

[0005] The technical solution adopted by this utility model to achieve the above objectives is: a transient response test system for a high-voltage capacitive voltage transformer, comprising a voltage regulating unit, a high-voltage vacuum switch control circuit, a phase selector, a reference voltage transformer, and electronic measuring equipment;

[0006] The output terminal of the voltage regulating unit is connected to the high-voltage vacuum switch, the capacitor of the test sample capacitive voltage transformer, and the reference voltage transformer.

[0007] The high-voltage vacuum switch control circuit includes a closing button and multiple branches connected to it; the multiple branches are located inside the high-voltage vacuum switch, and one end of the closing button connected to the multiple branches serves as a control terminal connected to the phase selector.

[0008] The electronic measuring device is connected to the secondary side terminals of the reference voltage transformer, the secondary side current transformer of the test sample capacitive voltage transformer, and the secondary side terminals of the test sample.

[0009] The voltage regulating unit includes a voltage regulator and a step-up transformer: the input terminal of the voltage regulator is connected to an AC voltage, and the output terminal is connected to the input terminal of the step-up voltage regulator; the output terminal of the step-up voltage regulator serves as the output terminal of the voltage regulating unit.

[0010] The output terminal of the voltage regulating unit is connected to the high-voltage vacuum switch, the voltage input terminal, the voltage input terminal of the capacitor of the test sample capacitive voltage transformer, and the voltage input terminal of the reference voltage transformer.

[0011] One end of the normally open contact of the closing button serves as the control terminal HA of the high-voltage vacuum switch control circuit, and is connected to the time relay module interface of the phase selector. The other end of the normally open contact is connected in series with the first branch and in parallel with the second and third branches.

[0012] The first branch includes: a normally open contact of relay CZ17, an auxiliary normally open contact of the limit switch CK in the high-voltage vacuum switch energy storage mechanism, one end of the normally closed contact of the first circuit breaker, a first rectifier bridge DX1, and a normally closed contact of relay CZ18 connected in series; the first input terminal of the first rectifier bridge DX1 is connected to the other end of the normally closed contact of the first circuit breaker, the second input terminal is connected to the normally closed contact of relay CZ18, and the output terminal of the first rectifier bridge DX1 is connected to the closing coil of the high-voltage vacuum switch energy storage mechanism;

[0013] The second branch includes: the normally open contact of relay CZ9, one end of the normally open contact of the second circuit breaker, the second rectifier bridge DX2, and the normally closed contact of relay CZ10 connected in series; the first input terminal of the second rectifier bridge DX2 is connected to the other end of the normally open contact of the second circuit breaker, the second input terminal is connected to the normally closed contact of relay CZ10, and the output terminal of the second rectifier bridge DX2 is connected to the trip coil of the high-voltage vacuum switch energy storage mechanism;

[0014] The third branch includes: the normally open contact of relay CZ15, the auxiliary normally closed contact of limit switch CK in the energy storage mechanism of high-voltage vacuum switch, the third rectifier bridge DX3, and the normally closed contact of relay CZ16 connected in series; the first input terminal of the third rectifier bridge DX3 is connected to the limit switch, the second input terminal is connected to the normally closed contact of relay CZ16, and the output terminal of the third rectifier bridge DX3 is connected to the motor of high-voltage vacuum switch.

[0015] The multiple channels of the electronic measuring device are respectively connected to the secondary side terminals of the reference voltage transformer, the secondary side current transformer of the test sample capacitive voltage transformer, and the secondary side terminals of the test sample.

[0016] The electronic measuring device is an oscilloscope.

[0017] This utility model has the following beneficial effects and advantages:

[0018] 1. This utility model connects an external 380V power supply to the transient response test system, uses a phase selector to set the zero-crossing point and peak and trough phase time control points, triggers the high-voltage vacuum switch to open and close, thereby realizing a primary short circuit in the voltage transformer, causing the voltage transformer to produce a transient response, and uses an oscilloscope to record the primary voltage and secondary voltage.

[0019] 2. This utility model can connect to 380V AC power supplies of different frequencies. This power supply can be a 50Hz power supply or a 60Hz variable frequency power supply. This power supply provides external power for the entire circuit. Through the transient response test system composed of a voltage regulating unit, a high-voltage vacuum switch control circuit, a phase selector, a reference voltage transformer, and electronic measuring equipment, it can complete the transient response tests of the two internationally common frequencies of 50Hz and 60Hz voltage transformers. It facilitates the measurement and wiring of the secondary terminals of the voltage transformer, simplifies the transient response test process, improves the overall test safety factor, ensures personnel safety, and improves the efficiency of transient response testing. Attached Figure Description

[0020] Figure 1 This invention relates to a high-voltage vacuum switch control circuit.

[0021] Figure 2 This is the electrical schematic diagram for the equivalent transient response test of the capacitive voltage transformer of this utility model.

[0022] Among them, 1 is the voltage regulator input, 2 is the step-up transformer input, 3 is the high-voltage vacuum switch start terminal, 4 is the reference voltage transformer start terminal, 5 is the phase selector, 6 is the oscilloscope, and 7 is the 380V AC power supply. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0024] A transient response test system for high-voltage capacitive voltage transformers utilizes a phase selector (which uses the time relay function of a microcomputer voltage and current synthesizer as the phase selector) to automatically capture zero-crossing and peak-crossing points. At these points, a high-voltage vacuum switch is triggered to achieve a short circuit. Compared to manual capture, this method captures waveform phase points more accurately, avoids repeated tests, and extends the service life of the high-voltage vacuum switch and oscilloscope. The control and measurement equipment are integrated and assembled to reduce the footprint of the equipment and the complexity of wiring.

[0025] A transient response test system for capacitive voltage transformers, such as Figure 1 As shown, the high-voltage vacuum switch control circuit controls the energy storage, closing, and opening of the high-voltage vacuum switch. In conjunction with the phase selector, it enables the primary voltage to control the closing of the high-voltage vacuum switch at its peak and zero-crossing points. The power supply provides AC 380V power for closing and opening operations. The closing button box is used to issue closing commands and control the on / off state of the closing circuit. Contacts 1 and 2 are normally open contacts of the closing button box in the high-voltage vacuum switch control circuit, and contacts 3 and 4 are normally closed contacts of the closing button box in the high-voltage vacuum switch control circuit, used to control the opening and closing of the high-voltage vacuum switch. The phase selector model is WTB-400B.

[0026] like Figure 1 As shown, the closing circuit uses a high-voltage vacuum switch: Relay contact CZ: plays a role in controlling the circuit's on / off state and transmitting signals; Rectifier bridge DK: converts AC power to DC, providing suitable DC power to the closing and opening coils. Closing coil HO and opening coil TO: generate electromagnetic force when energized, driving the high-voltage vacuum switch to perform closing and opening operations; Auxiliary contacts: such as CK and DL, are used to provide feedback on the switch's status information and participate in the circuit's logic control. Through the coordinated work of the above components, this circuit realizes the functions of closing and opening control of the high-voltage vacuum switch, as well as status monitoring. The high-voltage vacuum switch model is ZN28-12 high-voltage vacuum circuit breaker, and the high-voltage vacuum switch energy storage mechanism model is CT19 spring operating mechanism.

[0027] Figure 2This is the electrical schematic diagram for the transient response equivalent test, where T is the voltage regulator, YD is the step-up transformer, C1 and C2 are the capacitive voltage dividers, FT is the reference voltage transformer, CT is the through-type current transformer, and 6 is a four-channel oscilloscope: channel 1 is the primary voltage (power supply voltage), channel 2 is the secondary current (measured by a 100A / 100mV through-type current transformer), and channel 3 is the secondary voltage. The voltage regulator is connected to an external 380V AC power supply 7 to provide external power for the entire circuit. The output of the voltage regulator is connected to the input of the step-up transformer. The high-voltage output of the step-up transformer is connected to the first terminal of the capacitor under test, the first terminal of the reference voltage transformer, and the first terminal A 3 of the short-circuit switch. The first and last terminals of the phase selector 5 are connected to the control part (HA-N terminal) of the control circuit of the short-circuit switch, i.e., the high-voltage vacuum switch. Channel 1 of the oscilloscope is connected to the secondary side terminals 1a-1n of the reference voltage transformer to monitor the primary voltage. Channel 2 of the oscilloscope is connected to the secondary side ring CT of the test sample. The secondary measurement line passes through the middle of the ring CT to monitor the secondary current of the product. Channel 3 of the oscilloscope is connected to the secondary side terminals 1a-1n of the test sample to monitor the secondary voltage of the product.

[0028] To begin the experiment, first connect the output button on the voltage control panel. Figure 2 The 380V AC power supply is used. Rotate the voltage regulator handle to adjust the voltage regulator output voltage, which is then transmitted to the step-up transformer. The transformed voltage is then transmitted to the test object's capacitive voltage transformer 8 through the step-up transformer. First, apply a lower voltage, adjust the waveform height of the test oscilloscope, select an appropriate range, and calculate whether the heights of the primary voltage and the test secondary voltage match the actual voltmeter readings.

[0029] First, a trigger closing time T1 and a closing time T1+0.02S are set in phase selector 5. The output of phase selector is connected to... Figure 1 The vacuum switch control circuit is externally powered by AC 220V. When the phase selector trigger button is pressed, the power supply is AC 220V. When the closing button in the closing button box is operated (1-2 are normally open contacts, 3-4 are normally closed contacts), after the closing time T1, the circuit breaker DL closes. The current path is approximately: one end of the 220V power supply → normally open contacts 1-2 of the closing button box → CZ17 (relay contact) → auxiliary normally open contact of CK (when 7-8 is closed) → auxiliary normally closed contact of DL (when 1-3 is closed) → DK1 rectifier bridge → HO (closing coil) → CZ18 (relay contact) → the other end of the 220V power supply. The DK1 rectifier bridge converts AC to DC to power the closing coil HO, energizing the coil and generating magnetic force to drive the high-voltage vacuum switch to close, thus connecting the circuit. At the same time, the state of the auxiliary contacts in the closing circuit will change to provide feedback on the closing status and other information.

[0030] After the high-voltage vacuum switch trips in time (T1+0.02s), the current path is as follows: one end of the 220V power supply → CZ29 (relay contact) → normally open contact of DL (when 8-6 is closed) → DK2 rectifier bridge → TO (tripping coil) → CZ10 → the other end of the 220V power supply. The DK2 rectifier bridge converts AC to DC current, supplying power to the tripping coil TO, generating electromagnetic force to trip the high-voltage vacuum switch. Similarly, the state of the auxiliary contacts in the tripping circuit will change accordingly to provide feedback on the tripping status and other information. Simultaneously with the tripping, the motor M begins to store energy during the tripping process, preparing for the next closing and ensuring sufficient energy for closing.

[0031] After repeated adjustments, the four fixed delay times were finally determined: 0° positive crossing: 13.3ms, 90° positive peak: 20.1ms, 180° negative crossing: 25.1ms, and 270° negative peak.

[0032] Transient response analysis: First, apply a lower voltage using a voltage regulator. Adjust the waveform heights of channels 1 (primary voltage) and 3 (secondary voltage) of the oscilloscope, select an appropriate range, and calculate whether the heights of the primary voltage and the secondary voltage under test on the oscilloscope match the actual voltages. Then, apply 1.0 Upr (rated voltage of the test object), press the trigger button on phase selector 5, and short-circuit at the zero-crossing point of the primary voltage. Record the waveform, and measure the ratio of the secondary voltage Us(t) to the peak value of the secondary voltage √2Us before the short circuit at 20ms, 40ms, 60ms, and 90ms after the primary short circuit. When all four ratios satisfy the following condition If the transient response test of the current capacitive voltage transformer is deemed to be qualified, then the transient response test of the current capacitive voltage transformer is deemed to be unqualified.

Claims

1. A transient response test system for a high-voltage capacitive voltage transformer, characterized in that, Includes voltage regulating unit, high-voltage vacuum switch control circuit, phase selector, reference voltage transformer, and electronic measuring equipment; The output terminal of the voltage regulating unit is connected to the high-voltage vacuum switch, the capacitor of the test sample capacitive voltage transformer, and the reference voltage transformer. The high-voltage vacuum switch control circuit includes a closing button and multiple branches connected to it; the multiple branches are located inside the high-voltage vacuum switch, and one end of the closing button connected to the multiple branches serves as a control terminal connected to the phase selector. The electronic measuring device is connected to the secondary side terminals of the reference voltage transformer, the secondary side current transformer of the test sample capacitive voltage transformer, and the secondary side terminals of the test sample.

2. The transient response test system for a high-voltage capacitive voltage transformer according to claim 1, characterized in that, The voltage regulating unit includes a voltage regulator and a step-up transformer: the input terminal of the voltage regulator is connected to an AC voltage, and the output terminal is connected to the input terminal of the step-up voltage regulator; the output terminal of the step-up voltage regulator serves as the output terminal of the voltage regulating unit.

3. A transient response test system for a high-voltage capacitive voltage transformer according to claim 1 or 2, characterized in that, The output terminal of the voltage regulating unit is connected to the high-voltage vacuum switch, the voltage input terminal, the voltage input terminal of the capacitor of the test sample capacitive voltage transformer, and the voltage input terminal of the reference voltage transformer.

4. The transient response test system for a high-voltage capacitive voltage transformer according to claim 1, characterized in that, One end of the normally open contact of the closing button serves as the control terminal HA of the high-voltage vacuum switch control circuit, and is connected to the time relay module interface of the phase selector. The other end of the normally open contact is connected in series with the first branch and in parallel with the second and third branches.

5. The transient response test system for a high-voltage capacitive voltage transformer according to claim 4, characterized in that, The first branch includes: a normally open contact of relay CZ17, an auxiliary normally open contact of the limit switch CK in the high-voltage vacuum switch energy storage mechanism, one end of the normally closed contact of the first circuit breaker, a first rectifier bridge DX1, and a normally closed contact of relay CZ18 connected in series; the first input terminal of the first rectifier bridge DX1 is connected to the other end of the normally closed contact of the first circuit breaker, the second input terminal is connected to the normally closed contact of relay CZ18, and the output terminal of the first rectifier bridge DX1 is connected to the closing coil of the high-voltage vacuum switch energy storage mechanism; The second branch includes: the normally open contact of relay CZ9, one end of the normally open contact of the second circuit breaker, the second rectifier bridge DX2, and the normally closed contact of relay CZ10 connected in series; the first input terminal of the second rectifier bridge DX2 is connected to the other end of the normally open contact of the second circuit breaker, the second input terminal is connected to the normally closed contact of relay CZ10, and the output terminal of the second rectifier bridge DX2 is connected to the trip coil of the high-voltage vacuum switch energy storage mechanism; The third branch includes: the normally open contact of relay CZ15, the auxiliary normally closed contact of limit switch CK in the energy storage mechanism of high-voltage vacuum switch, the third rectifier bridge DX3, and the normally closed contact of relay CZ16 connected in series; the first input terminal of the third rectifier bridge DX3 is connected to the limit switch, the second input terminal is connected to the normally closed contact of relay CZ16, and the output terminal of the third rectifier bridge DX3 is connected to the motor of high-voltage vacuum switch.

6. The transient response test system for a high-voltage capacitive voltage transformer according to claim 1, characterized in that, The multiple channels of the electronic measuring device are respectively connected to the secondary side terminals of the reference voltage transformer, the secondary side current transformer of the test sample capacitive voltage transformer, and the secondary side terminals of the test sample.

7. The transient response test system for a high-voltage capacitive voltage transformer according to claim 1, characterized in that, The electronic measuring device is an oscilloscope.

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