E-Field distribution of circuit with value controlled reactors in 750 kV substations

Since 750 kV transmission lines locate in the high altitude areas of northwest China where the environment condition is comparatively severe, the electromagnetic environmental problems in substations appear to be more prominent. As can be seen from the field observation results of the in-service substation, the frequent or permanent presence of corona discharge is obvious adjacent to the corona rings and end fitting hardware. This can result in distinct consequences of radio interference and audible noise, thus it may necessitate reasonable design of corona rings to improve the E-Field conditions. In this article, using a three-dimensional finite element method model, the E-Field distribution of circuit with value controlled reactors in the 750 kV substations is researched. According to both actual knowledge of phenomena and practical experiences form test facilities and lines in operation, a viable value of E-Field intensity is ascertained to control the electric field, and the configurations of some corona rings are optimized subsequently to diminish the corona discharge. And then an exhaustive suggestion about the design and arrangement of corona rings is proposed. The results could provide experiences and references for the design of 750 kV AC substation, and better technical performance and economic competitiveness is predicted to be implemented.