Gas high-voltage transformerIt has the characteristics of small size, light weight, not affected by climate change, low corona, no need to be stationary for on-site handling, long service life, and maintenance free. Suitable for conducting insulation strength tests on various high-voltage electrical equipment, electrical components, and insulation materials under power frequency or DC high voltage in power systems, industrial and mining enterprises, scientific research departments, etc.
In the power frequency withstand voltage test, the measurement of voltage (instrument voltage) on the low voltage side is not very accurate. The reason is that the test transformer has leakage reactance, and there must be voltage drop or capacitance rise on this leakage reactance, which causes the voltage on the test sample to be lower or higher than the voltage reflected on the low voltage side measurement voltmeter. During the power frequency withstand voltage test, the voltage on the test object is higher than the output voltage of the test transformer, which is known as the capacitance rise phenomenon. During the induction withstand voltage test, there must be a voltage drop in the leakage reactance of the test transformer. In order to accurately measure the voltage applied to the test sample, an FRC resistive capacitive voltage divider is often connected to the high voltage side to measure the voltage.
Precautions for operating the power frequency withstand voltage test:
1) Test personnel should divide their work and clarify their methods with each other. And there are dedicated personnel to monitor on-site safety and observe the status of the test samples.
2) The test sample should be cleaned and dried first to avoid damage to the test sample and errors caused by the experiment.
3) For large-scale experiments, an air lift test should generally be conducted first. Raise the voltage to the test voltage without connecting the test sample, calibrate various meters, and adjust the ball gap.
4) The boosting speed cannot be too fast and sudden boosting must be prevented. For example, when the voltage regulator is not at zero position, it suddenly closes. It is also not possible to suddenly cut off the power supply. Generally, the circuit breaker should be tripped when the voltage regulator drops to zero.
5) When the voltage rises to the test voltage, start timing. After 1 minute, quickly reduce the voltage to below 1/3 of the test voltage before turning on the power supply.
6) If any of the following abnormal situations are found during the boost or withstand voltage test, the voltage should be immediately reduced and the power supply should be cut off. Stop the experiment and investigate the cause: ① The pointer of the voltmeter swings greatly; ② Discovering insulation burning or smoking; ③ There is abnormal sound inside the test sample.
7) Before and after the withstand voltage test, the insulation resistance should be measured to check the insulation condition.