Characteristics of Overvoltages in 500  <scp>kV</scp> Gas‐Insulated Switchgears Caused by Multiple Direct Lightning Strokes

Generally, lightning protection design for a substation has been mainly based on the lightning overvoltage caused by a back flashover occurring at a transmission tower near a substation. It has been reported that electrical breakdown occurred between the moving and fixed contacts of a 500‐kV gas circuit breaker (GCB) because of multiple direct lightning strokes. In a previous study, installing an additional lightning surge arrester (SA) close to the GCB was proposed to protect the GCB from steep‐front subsequent lightning stroke currents. However, no lightning surge analysis for gas‐insulated switchgears (GISs) considering multiple direct lightning strokes has been performed. In order to evaluate the need for countermeasures for GISs against multiple direct strokes, the lightning surge analysis results carried out for a 500‐kV GIS are presented in this paper. © 2026 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.