1.1 Calibrate the waveform parameters: front time 1.2 µs±30 %, tail time 50 µs±20 %, maximum amplitude accuracy ±3 %. Check the grounding system is intact and reliable, the operation area is divided into warning lines and set up grounding rods

1.2 Install the 35 kV 600A oil-immersed casing firmly on the support according to the test stand drawing, and ground the metal flange part of the casing. 2.

1.3 Install the 35 kV 600A oil-immersed casing firmly on the support according to the test stand drawing, and ground the metal flange part of the casing. 2.

1.4 Carry out at least 5 positive and negative shocks at 5 % to 10 % of the rated shock withstand voltage (Uᵢₘₚ) to eliminate local defects. Measure and record the waveforms of each time to confirm that the leading edge, trailing wave, ringing and other indicators meet the requirements.

1.5 According to the technical requirements of the casing, apply the lightning impact voltage of 200kV one times each in the positive and negative directions, record all the waveforms, and check that there is no flashover and no breakdown. And check all value are in the range ans clause 1.1