Study on VPI Manufacture Technology of Stator Bar for 200MW Air-Cooled Turbo-Generator

Abstract

The dry mica tape and impregnation resin were introduced in this paper, which were main insulation materials of 200MW air-cooled turbo-generator stator bar manufactured by VPI (vacuum pressure impregnation) technology. The insulation manufacture technology, corona protection technology and properties of real products also were introduced in this paper. The results show that the electrical properties of the stator bars made by this kind of VPI technology reached the top level of the world which could be seen as follows: there is no discharge appeared during the AC high voltage potential test when the test voltage was 3UN, the dissipation factor tgδ under 0.2UN is lower than 1%, and the increment Δtgδ=tgδ0.6UN- tgδ0.2UN is lower than 0.5%, when the voltage applied is from 0.2UN to 1.2UN. The magnitude of maximum partial discharge is only 90pc to 110pc, the instantaneous breakdown strength of the bars are all higher than 34kV/mm, under the field of 8.73 kV/mm, the lest enduring time of the test bar is 1500h.