Research on 220kV GIS enclosure circulation and temporary ground potential rise

Enclosure circulation of Gas Insulated Switchgear (GIS) and Very Fast Transient Overvoltage (VFTO) are harmful to many respects of power system, including system's security, stability and economic. The effective inhibition of GIS enclosure circulation and VFTO has attracted wide attention. In this paper, GIS enclosure circulation and transient ground potential has been modeled and analyzed. Firstly, this paper discusses the GIS enclosure circulation VFTO, Transient Grounding Potential Rise (TPGR) and the harm, as well as its domestic and foreign researching status. Then, a simplified model has been established, according to which, the steady-state operation of GIS enclosure and connected network circulation theoretical calculation have been investigated according to the GIS shell and grounding grid circulation. The software ATP/EMTP is utilized in the simulation, which takes gas insulated equipment shell connection mode, shell grounding layout and grounding and the grounding grid structure into account. According to the results of theoretical calculation and simulation, the comprehensive optimization of the enclosure circulation and transient potential can be effectively improved and some prevention measures also can be proposed from the deeper understanding of grounding line number and distribution of circulation inhibition. Theoretical results can provide significant reference for the power grid design, operation and protection.