Before operating the power frequency withstand voltage test device, the maximum working current should be calculated based on the capacity and voltage level of different test objects, and the current protector should be adjusted accordingly. The test wiring should refer to the wiring diagram in this manual and must be reliably grounded.
Operation point
(1) Before the experiment, it is necessary to understand the test voltage of the test sample, as well as other test items and previous test results of the test sample. If the test sample has defects or abnormalities, it should be eliminated before conducting the withstand voltage test.
(2) The test site should be surrounded by barriers or ropes, hung with signs, and monitored by a designated person
(3) Before the experiment, the surface of the test sample should be wiped clean, and the outer shell of the test sample and the non test winding should be reliably grounded. When the test sample is a new oil flushing equipment, the oil should be allowed to stand still for a certain period of time according to the regulations before boosting. For oil filled power equipment of 110kV and below, the static time after filling with oil should not be less than 24 hours. For oil filled power equipment of 220kV and 330kV, the static time should not be less than 48 hours.
(4) After connecting the test wiring, experienced personnel should check and confirm that there are no errors before boosting the voltage.
(5) Before boosting, first check if the regulator is in the zero position. The voltage regulator can only boost the voltage when it is at zero position.
(6) During the boosting process, not only should the changes in the voltmeter be monitored, but also the changes in the ammeter and the current of the test object should be monitored. When boosting, the pressure should be evenly increased and not too fast. When the specified test voltage is reached, start calculating the time. After the time is up, slowly and evenly decrease the voltage. Never allow the power switch to be turned off without voltage reduction.
(7) If the pointer swings or there is abnormal noise or smoke from the test object during the experiment, the voltage should be immediately reduced, the power should be turned off, and a grounding wire should be hung on the high voltage side before investigating the cause.
(8) The insulation resistance of the test object should be measured before and after the withstand voltage test.