Lightning Overvoltage Analysis of Bus Tie Circuit-breaker Fault in 220 kV Banqiao Substation

In accordance to lightning-caused breakdown of insulator supporting fixed contact of phase W of bus tie circuit-breaker on 220 kV line B of Banchen line of 220 kV Banqiao substation,three simulation models for gas insulated metal enclosed switchgear and controlgear(GIS) in condition of severe lightning intruding surge are established by means of ATP for simulation analysis of lightning overvoltage.It is determined that the fault results from foreign body and dust on the insulator surface,which causes insulator property reduction and eventually surface flashover of external insulation under action of both reflected lightning wave and power frequency voltage.Anti-accident measures for strengthening GIS are proposed.