Analysis of Bolt Overheat in 220kV GIS

In this paper, a bolt overheat situation, reaching 126 degrees, occurred on a 220kV GIS (gas-insulated metal-enclosed switchgear) was discussed. The grounding features of GIS as well as the problems arising from poor grounding were analyzed. Based on the application of characteristics of electromagnetic field in GIS, the circulating current and eddy current in alternative electromagnetic field are calculated. Also, the associated factors in the induced current of the grounding structure are discussed. Moreover, this paper proposed maintenance plan with minimal change, which is proven effective.