Patent ID: 7388384
Filing Date: 2008-06-17
Classification: G01R

Abstract:
1. A method of monitoring partial discharge in a gas-insulated apparatus and diagnosing a failure condition by sensing an intensity of a partial discharge signal caused by a defect, comprising the steps of: a) detecting a partial discharge signal caused by a defect by multiple sensors disposed apart from each other; b) frequency analyzing the detected partial discharge signal and judging a type of the defect based on a signal of the partial discharge signal which is synchronized with the frequency of the voltage applied to the gas-insulated apparatus by using a defect type database; c) calculating a location where a partial discharge occurred and a strength of the partial discharge based on the partial discharge signal detected by the multiple sensors; d) calculating a conductor surface field strength and a field unevenness factor at the location where the partial discharge occurred, based on the calculated position of the partial discharge, by using a structural dimension database; and e) estimating a size of the defect based on the intensity of the partial discharge and the calculated conductor surface field strength and the field unevenness factor at the location where the partial discharge occurred by using a defect size database corresponding to a type of defect within defect size databases provided for a plurality of types of defects.