Investigation and Suggestions for the Overheating of Contacts in ZS1 Type Medium Voltage Switchgear

During overhaul of a power station,it was found that the contacts of the power supply incoming line switch cabinet were grey-black and showed obvious signs of overheating.Through inspection and analysis,it was discovered that the silver plating on the static contacts of the switchgear and the contact fingers of the circuit breaker had been sulfidized, leading to excessive contact resistance and overheating.After removing the sulfidized layer on the static contact surface and replacing the contact fingers of the circuit breaker,the contact resistance returned to normal.This paper proposes some suggestions for dealing with the sulfidation of conductive silver plating on engineering practice,which can be referred to by peers.