To evaluate the insulation strength of a generator, thefrequency conversion series resonance test equipmentand the power frequency AC withstand voltage test are the most effective and direct ways, because the waveform frequencies of the voltage and working voltage in the power frequency AC withstand voltage test are the same, which will have important decisive significance for determining whether the generator can be used. Therefore, the power frequency AC withstand voltage test is a very important test in the generator insulation test.

It should be noted that before conducting the AC withstand voltage test, it is necessary to comprehensively analyze and judge other non-destructive testing results such as insulation resistance, absorption ratio, leakage current, etc., and then decide whether the generator can undergo the withstand voltage test to avoid excessive insulation breakdown during the test.

How to conduct AC withstand voltage test for series resonant generator, the specific operation is as follows:

The overcurrent protection shall be based on 1.2 times the rated current of the high-voltage side of the test transformer.

For example, on the high voltage side of a 50A transformer with a rated excitation current, the transformer is configured as 50/5, and its current relay should be adjusted to a value of 5A.

The overvoltage protection is set to 1.1 times the test voltage.

For example, when the test voltage is 39 kV, the display should be adjusted to 43 kV.

Connect the voltage divider cable to the high-voltage two terminal post on the control console. Please note that all grounding wires must be securely and reliably connected.

Connect the excitation voltage to the two high-voltage current control console terminal current transformers. 

Voltage endurance time setting: Set the test time on the time relay to the required test time.

After checking the wiring for correctness, the console circuit breaker is closed. If the adjuster is not in the zero position, it will automatically return to zero. Do not turn on the main power supply, adjust the core clearance of the reactor, and observe whether the lifting and net limit protection functions are normal.

Turn off the main power supply, press the "boost" button, and boost the voltage to the reactor to obtain hundreds of volts. Adjust the output voltage to the highest by changing the air gap. At this time, the high voltage can be adjusted. When the voltage reaches the test voltage value, it will automatically withstand the timing and reach the set withstand time. The equipment will automatically reduce the voltage to zero. Cut off the main power supply. During the experiment, relevant personnel should strengthen the monitoring of the tested equipment. When abnormal phenomena occur, the voltage regulator should be quickly lowered and the power supply should be disconnected at the same time.