Effect of External Insulation Environment on Electric Field Distribution of 500kV Porcelain Bushing

Electric field distribution in porcelain bushing for 500kV SF6 tank breaker is of great significance for safe and stable operation of breaker. There are many factors affecting the distribution of electric field inside the bushing. From the point of view of safe and stable operation of the equipment, the environmental conditions such as rain and snow contamination outside the bushing are fully taken into account in this paper. The electric field distribution inside the bushing is simulated and analyzed. The highest local electric field which may occur inside the bushing is obtained, compared with the breakdown field strength of SF6 and assess the reliability of bushing insulation structure. The results show that the external environment has little influence on the electric field distribution in the bushing. In the operation of the equipment, the change of the external environment and the overvoltage can hardly make the internal insulation failure.