Comparison Study On GIS Partial Discharge Detection Based On UHF, Ultrasonic And Conventional Methods

With the increasing demand for electric power, the application of HV GIShas become more and more popular in power grid. Due to the compactconfiguration, GIS withstands much higher field intensity. It is necessary tojudge the insulation state of GIS precisely, in order to ensure its reliabilityand availability. Partial discharge detection under alternating voltage is animportant approach to investigate the insulation state of GIS. According tothe researches, different defects of GIS can lead to different phasedistribution characteristic patterns of partial discharge. Evaluating andjudging the defects of GIS through the study of these patterns is veryimportant to the safe operation of GIS.Depended on this background, this paper aims to study and compare thesepatterns via the test on simulated defects. The patterns are obtained throughdifferent methods of partial discharge detection (UHF, Ultrasonic, andconventional method). So that we can have a deeper understanding of thecharacteristics of partial discharge and further are able to evaluate and judgethe insulation state of GIS.This paper also introduces the theory of the GIS partial discharge, studiesthe PD process, analyses partial discharge impulses and describes differentkinds of insulation defects in details. After that, three most widely usedmethods of partial discharge detection are discussed: conventional, ultrasonicand UHF method. Other parts of the paper cover testing devices and systemsused in the test; it also describes how to simulate different kinds of GISdefects.