Research on Lightning Overvoltage Simulation and Protective Measures of 10kV Distribution Transformer

The lightning disaster will directly invade into the 10kV/0.4kV distribution transformer installed on the line tower through the line, resulting in high overvoltage inside the transformer. Distribution transformer is an important part of the distribution network. Lightning current invades into the distribution transformer along overhead line, which will cause internal overvoltage and lead to insulation breakdown of high voltage side winding or low voltage side winding. In this paper, the broadband equivalent model of transformer is established, and the lightning overvoltage intrusion simulation of transformer is carried out. The changes of high voltage side voltage and low voltage side voltage of transformer are analyzed when the single-phase incoming wave of direct lightning and the three-phase incoming wave of induction lightning, and the corresponding protective measures are analyzed.