Evaluation Methodology About the Effect of the Sophisticated Test of GIS

According to the related regulation, the sophisticated test of GIS is a necessary experiment project before conducting the AC voltage withstand test. But there is not an appropriate evaluation methodology to evaluate the effect of the sophisticated test. This chapter presents a method to evaluate the effect of the sophisticated test and diagnose the insulation defects. This method extracts the transient voltage and current which can be measured in the voltage step-up process as the information sources. As the voltage and current contain a large number of harmonic components which involve a great deal of information of the effect of the sophisticated test, they can generate the recognized criterion which is closely related to the harmonic components. The effect of the sophisticated test can be assessed, according to the extreme value distribution of the identification function. This methodology helps to improve the efficiency of the sophisticated test of GIS.