GIScommunicationWithstand Voltage TestUsually, the method of frequency conversion voltage resonance is adopted. By adjusting the output frequency of the frequency conversion power supply, voltage resonance occurs in the circuit. Then, the output voltage of the frequency conversion power supply is adjusted to reach the test voltage value. The test frequency can be adjusted within a certain range, with high quality factor and no 'test dead zone'. Moreover, the protection function of the test equipment is complete, which can effectively protect the test sample.Our technical personnel assisted the user in successfully completing the on-site testing guidance, and the customer was very satisfied with our service!

GIS AC withstand voltage testrequirement

During the GIS field test, the weather conditions have a significant impact on the quality factor Q value, which is (L/C) 1/2/R. However, as the test voltage gradually increases, corona occurs in the test circuit, and the active power loss R also increases, resulting in a decrease in the quality factor Q. In cloudy or humid conditions, the quality factor Q value will decrease by about 30%, resulting in an increase in the input voltage of the excitation transformer. Therefore, the withstand voltage test of GIS must be conducted on sunny days or in dry air. According to the GB 7674-1997 standard, the AC test voltage value for GIS is 80% of the factory test voltage value, with a frequency of 10-300 Hz. The selection of the GIS test plan requirements shall be jointly agreed upon by the testing unit, GIS manufacturer, and user. The experimental process is generally divided into two stages: 'seasoned test' and 'withstand voltage test'. Due to differences in GIS manufacturers, the experimental plan may also vary slightly.

During the 'maturity test' phase (including TA, TV, BLQ), the test voltage is gradually increased from zero to 73 kV for a 5-minute withstand voltage test. The maturity test can be conducted separately for each phase or simultaneously for all three phases, and then the test voltage is gradually reduced to zero.

After cutting off TA, TV, and BLQ in the 110 kV GIS, separate phase withstand voltage tests are conducted. The test voltage is gradually increased from zero to 126 kV for 5 minutes, and then the test voltage value is further increased to 184 kV for 1 minute of AC withstand voltage test.