Analysis of the insulation structure and electrical distribution of 1100-kV OIP condenser transformer bushings in China

In this paper, the technical parameters, main dimensions, structural design, and the electrical field distribution of a 1100-kV AC oil-impregnated paper (OIP) condenser transformer bushing used in the Wuhan (China) ultrahigh-voltage (UHV) experiment are presented. The electrical field calculations of the bushing, which is composed of the condenser, the lower porcelain housing, the grading ball, the transformer lifting seat, and the insulated oil, are performed and the parameters of the grading rings are optimized. The electrical field distribution curves of the bushing at 1.5 m height to ground are also drawn. By studying and experimenting on the 1100-kV bushing, the inner and the outer insulation structure of the bushing were found to be proper; the radial and the axial electrical fields meet the design requirement; the performance parameters of the bushing are in accord with the corresponding standards and technical specifications. The bushing has already passed the type tests and works well at the Wuhan UHV AC experimental base. This establishes a good foundation for the design, manufacture, and experimentation on the 1100-kV AC OIP condenser transformer bushing. (c) 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.