Electric Field Analysis and Research of 1000 kV AC Transformers High Voltage Direct Type Exit Device

At present, two kinds of high voltage exit devices are used in 1000 kV transformer products, direct exit and indirect exit devices. The structure of the high voltage exit devices must have reliable insulation. Two kinds of structures of the exit devices of UHV transformer are presented and analysed with ElecNet electric field analysis softwares by the authors in this paper. The global two-dimensional and three-dimensional electric field analysis is carried out for the high voltage horizontal and vertical lead pipe to exit device. Because of the complexity and importance of the exit device, it is necessary to design the shape and size of the insulator reasonably. The creepage analysis of the support insulation structure of the exit device is carried out by using the commercial software and self-developed creepage analysis software respectively. Also provides economic comparison of two ways. The indirect exit device has certain advantages in economy, technology and design simplification. It will be widely used in power grid construction.