The Research And Optimization Of Electric Field Of UHV Power Transformer

In order to realize the optimization of China's energy resources, study on the technology of ultra high voltage power transmission must be strengthened. In order to master the core technology of UHV products and electric field mechanism, we actively promote the research and development of ultra high voltage series products, and strengthen the basic research of UHV transformer. The insulation structure of UHV Transformer is analyzed in this paper. The main contents of the paper are as follows.Firstly, the principle of the design of UHV insulation structure is systematically introduced. and the development of the analytical method of insulation electric field by analytical method to finite element method is described.Secondary, this paper presents an example of the electric field analysis of end insulation and exit device of the UHV transformer based on the finite element method(FEM),.optimize electric field by adjusting the parameters such as insulation thickness, radius of curvature of the electrostatic ring (SER), cylinders arrangement etc. In this paper, the principle of insulation strength evaluation under the breakdown field stress is described.Then, in the design of the main insulation of UHV transformer, the field stress in transformer oil is mainly considered. At the same time, breakdown field stress and creepage stress are both need to be considered. For example, the angle ring not only plays a role in the segmentation of the gap, but also improve the oil/board interface distance, the design principle of the contour of the angle ring is the coincidence of the potential line, these are important measures to improve the creepage stress. In this paper, two methods of evaluation creepage strength (tangential field strength) along the oil/ paper interface are introduced. And the evaluation program of creepage stress analysis is developed, which based on the above two methods. The examples for analysis on creepage stress at winding end and exit device are presented. The secondary development program can be applied to two dimensional and three dimensional analysis on creepage stress. At present, there is no three dimensional analysis and calculation software on creepage stress, the secondary development program has the very vital significance.