The Detecting Methodology of GIS Insulation Defects Based on the AC Withstand Voltage Test

Abstract

AbstractThe AC withstand voltage test is the most common method of GIS (Gas Insulated Switchgear) on-site withstand voltage tests. The AC withstand voltage test exists in a voltage step-up process, and the voltage waveform contains harmonic components. This chapter presents a new method to diagnose the insulation defects by applying the transient voltage and current generated in the voltage step-up process. This method takes the transient voltage and current as information sources and decomposes the transient voltage and current into a series of harmonic components which are taken as the sample data set. We put the sample data into the reference database and get the numerical values of correlation coefficient. When the value reaches its maximum, the sample data set has the highest similarity to one specific reference data set. According to the known insulation fault information of this specific reference data set, we can get more insulation fault information of this GIS than the AC withstand voltage test. This method can availably get the detailed local fault information of GIS and also detect whether the GIS has the insulation damage after the GIS pass through the AC withstand voltage test or not.KeywordsInsulation DefectsWithstand Voltage TestTransient VoltageInsulation DamageSpecific Reference DataThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.