The lightning disaster will directly invade the 10kV/0.4kV distribution transformer installed on the line tower through the line, resulting in a very high overvoltage inside the transformer. The distribution transformer is an important part of the distribution network. The lightning current intrudes into the distribution transformer along the overhead line, which will cause its internal overvoltage and lead to the insulation breakdown of the winding on the high voltage side (low voltage side) of the transformer. In this paper, the broadband equivalent model of transformer is established, the lightning overvoltage intrusion simulation of transformer is carried out, and the changes of neutral point potential and high and low voltage side voltage of transformer during direct lightning single-phase forward wave and induced lightning three-phase forward wave are analyzed, and the corresponding protective measures are analyzed.

Distribution transformer,Lightning overvoltage,Protective measures