고압전동기 고정자권선 오염에 의한 고전압 절연진단 시험 중 연면방전 사례

This paper is purpose to understand the surface discharge properties of the contaminated high voltage motor stator windings. we carried out the insulation diagnostic tests for the contaminated 6.6㎸ motor in power plant. During the high voltage test, the flash-over occurred at 6.1㎸. We couldn't make sure if the ground -wall insulation was broken or it was just a surface discharge between an end-winding and the stator core. So we washed-out the stator windings with steam and dried in 110℃ during the 48 hours. and we carried out the insulation diagnostic tests and dielectric strength again. the insulation diagnostic tests are consist of the megger, the polarization index, the AC current test, the dissipation factor test and the partial discharge test. we analyzed the test results of the flash-over before and after.