Lightning transient simulation and analysis of EGLA under single-ended circuit breaker open system

The lightning strike overvoltage is the main reason which causes the overhead transmission application of externally gapped line surge arrester (EGLA). When single-ended gas circuit breaker (GCB) is required by system power flow with normal open. However, under the normal open conditions, when a lightning overvoltage strikes overhead transmission lines at the export of substation, flashover may occurs from the arc horn of post insulation of air-break switch (ABS) or even burning accident of GCB occurs. This paper presents the study of lightning surges performance transient overvoltage in a 69kV circuit breaker normally open system. Then, major criteria suggested by IEEE and IEC standards are used to assess the level of insulation coordination of a 69kV circuit breaker normally open system.