Insulation faults of high-voltage switchgear are mainly manifested as external insulation-to-ground flashover breakdown, internal insulation-to-ground flashover breakdown, phase-to-phase insulation flashover breakdown, lightning overvoltage flashover breakdown, porcelain bushing, capacitor bushing flashover Networking, pollution flashover, flashover, breakdown, explosion, lifting rod flashover, CT flashover, breakdown, explosion, porcelain bottle fracture, etc. Various insulation defects develop to the final breakdown, and they often go through the partial discharge stage before they lead to accidents. The strength of the partial discharge can reflect the insulation status in time. Therefore, the online monitoring of the partial discharge to determine the insulation status is to realize the online monitoring of the switchgear insulation. And effective means of diagnosis.