Firstly, this is related to the material of the transformer cabinet casing. Most transformer cabinet casings in China may be mainly made of metal, which contains good conductivity and ductility. The internal electrical equipment voltage is too high, and there are high-density conductive particles in the powder air in the internal space. The conductive particles combine with the voltage to break through the metal casing, causing the box to conduct electricity.

It may be related to the circuits around the substation cabinet. The pre buried circuits around the substation cabinet have aged many circuits due to long-term sedimentation, and the surrounding environment of the substation cabinet is humid, which leads to the electrification of the substation cabinet shell and is related to the grounding of the substation cabinet. In order to avoid lightning strikes, grounding devices are added during the installation process of each substation cabinet. An insulated casing is placed outside the grounding, which may be due to the wear of the insulation casing and the trace electrical particles stored in the substation cabinet due to lightning strikes.

Article source: Jiangmen substation cabinet http://www.gdsandingdianqi.com/