A lightning disaster on an oil well was investigated

and the relative data

such as residual magnetism at deformed part of storage tank and grounding resistance

were collected for analyzing the causes of the lightning disaster on the oil well facilities.Calculation results show that the overvoltage on the deformed part of the storage tank under direct lightning was up to 2 100 kV

the overvoltage on the 10 kV transformer was 180 kV

the overvoltage on the 1 140 V motor was 20.8 kV

and the overvoltage on TV was 4 014 V

all of which exceed the critical values of the corresponding equipments.Consequently

some direct lightning protection measures for storage tank

oil pumping machine

electric motor and transformer are discussed on the basis of the theoretical analysis.For overvoltage protection

it is suggested that a zinc oxide lightning arrester with rated voltage 15 kV be installed at high voltage side of the transformer

a surge suppressor with 8/20 μs waveform and 80 kA SPD flow be set at the first level of subsequent transmission line

and a surge suppressor with 8/20 μs waveform

40 kA SPD flow and residual voltage lower than the equipment withstand voltage be set at the second level.