Simulation and Test of Double-fracture Disconnect Switch in GIS

The double-fracture disconnect switch(DDS) is a solution to continue operating without shutting down during GIS extension and withstand tests, which is designed as an nonstandard structure. In order to verify that the DDS satisfies the actual operating conditions. In this paper, the 3D simulation models of DDS for the mechanical, electrical, thermal field are established by ANSYS. The simulation calculation of mechanical strength, insulation strength and current-carrying capability of the DDS are carried out. In addition, the insulation test, temperature-rise test, dynamical thermal stability test, mechanical life test, shell water pressure test are carried on the real DDS as well. The results show that the maximum stress of the shell is 235.08MPa, and the maximum stress of cover plate is 114.86MPa, which are both less than the allowable stress. It also shows that the electrical field of each component in the DDS is lower than the allowable field strength. As for the temperature test, the maximum temperature rise of sliding joint and the shell are 56.5K and 17.3K. Temperature rise of both internal conductor and shell meet the requirements. In sum, the experimental results consistent with the simulation calculation. The DDS has been applied to 6 standby expansion intervals of 220kV GIS in the ±800kV Dong-Fang converter station.