1、 After connecting the line according to the multiple pulse method on site, it is normal to apply impact high voltage if a more ideal test waveform is not obtained. Because the distance of the fault is not known in advance, the electrical strength of the fault point is not clear. If the impulse voltage is not high enough and the fault point is not broken down by the impulse high voltage to produce arc, the fault echo cannot be collected. At this time, only the open circuit waveform of the terminal can be seen. The impulse voltage must be increased until the fault echo is seen.

2、 Sometimes the fault point is far away from the test end and the echo is weak, so the "length selection" must be adjusted to obtain a strong fault echo. The cable fault tester has three states of "short distance", "medium distance" and "long distance". "Short distance" is suitable for testing faults within 1km, "medium distance" is suitable for testing faults within 1 ~ 3km, and "long distance" is suitable for testing faults within 3 ~ 16km.

3、 In order to ensure full breakdown of fault point and sufficient arc duration, it is recommended to use 2 μ F energy storage capacitor with withstand voltage above 35kV.

4、 In the process of multiple pulse method test, there is a "pulse generator" in series between the high-voltage equipment and the faulty cable. The impact high voltage actually added to the cable fault phase is lower than the output voltage of the high-voltage generator. If the output voltage of the high voltage generator has reached 35 ~ 42KV and the fault point has not broken down, the impulse high voltage flashover current sampling method shall be replaced for testing.