Abstract: When the dianzhuang operation team inspected the 6kV high voltage room of Bieguzhuang substation on January 3, 2022, it was found that some equipment operation and display devices sent out a disconnection alarm. The technicians and maintenance personnel analyzed this new fault. Judge that the "disconnection alarm" is sent by the electric heating plate controller circuit, which will cause the electric heating plate to exit operation. In order to avoid the impact of temperature and humidity changes caused by severe cold factors on the safety of the equipment, they made small improvements to the operation and display device in time, dealt with this fault, and ensured the safe operation of the equipment in Bieguzhuang substation.