1. AC withstand voltage test for 6kV-500kV high-voltage cross-linked cables
2. Power frequency withstand voltage test for 6kV-500kV transformers
3. AC withstand voltage test for GIS and SF6 switches
4. AC withstand voltage test for generators
5. AC withstand voltage test for other high-voltage power equipment such as busbars, bushings, and instrument transformers.
Usage:
1. With voltage regulator (3kVA~10kVA)
1) Connect according to the wiring diagram, then adjust the overcurrent protection current value based on the test object.
2) Set the voltage regulator to the lowest position, close the power switch, check if the zero-position indicator light is on, and verify for phase loss, then start the test bench.
3) Adjust the voltage regulator so that the triple-frequency output voltage reaches the test voltage. Use an oscilloscope to measure the output voltage waveform, frequency, and output voltage value to meet the test requirements of the test object.
4) After the test, adjust the voltage regulator to bring the triple-frequency output voltage to zero, ensure the zero-position indicator light is on, then open the switch.
5) Cut off the power supply and end the test.
2. Without voltage regulator (10kVA~1000kVA)
1) Connect according to the wiring diagram, then adjust the overcurrent protection current value based on the test object.
2) Set the inductor to the high position, turn on the power switch, check for phase loss, and start the test bench.
3) Adjust the inductor handle to increase the voltage on the voltmeter. When the current is at the minimum, resonance occurs, reaching the test voltage value. Measure the output voltage waveform, frequency, and output voltage value until the test power requirements of the test object are met.
4) After the test, adjust the inductor handle to reach the high position.
5) Cut off the power switch and end the test.
Product Features
The primary sides of three single-phase transformers are connected in a star configuration, and the secondary sides are connected in an open delta. When a symmetrical three-phase sinusoidal power supply is applied to the primary side, the voltage is raised to saturate the iron core magnetic circuit, increasing the third harmonic component in the magnetic flux. Correspondingly, the third harmonic voltage induced in the iron core coil also increases.
The 150 Hz (triple power frequency) induced voltage output from the secondary side of the open delta generator serves as the triple-frequency test power supply voltage.
When the triple-frequency generator is loaded with (for example, JCC——220 type high-voltage cascade voltage transformer), the current changes from inductive to capacitive. Due to the low power factor, the generator's efficiency is relatively low, generally only about 20%. Therefore, a reactor can be connected to a certain empty winding of the test object for current compensation to improve the power factor of the entire test circuit. Product Application
It is a lightweight testing device that utilizes the saturation characteristics of the magnetization curve of silicon steel sheet cores in the power frequency grid, inducing a zero-sequence third harmonic potential in the secondary coil of the transformer connected in an open delta configuration.
