Insulation aging in 12 kV switchgear-a users perspective

Study on the lightning strike discharge characteristics of switchgear air gap at low air pressure condition

“…Also, the 40.5 kV switchgear should pass 1 min lightning impulse withstand voltage of 185 kV [9]. However, with the increasing aging problems during long-term operating, the devices cannot always satisfy the insulation level, so relevant accidents are frequently reported [10][11][12].…”