A Study on Insulation Diagnosis and Partial Discharge Interpretation for an 800kV Power Transformer in NPP

This paper shows how to detect the partial discharges generated in a power transformer and several methods to diagnose the equipment more precisely. For this purpose, the main transformer (GSU: Generator Step-up Unit) in a nuclear power plant that had been generating the acetylene gases for a while will be introduced as below. This analysis has been done through two ways of diagnosis on a transformer in NPP. It is certain that performing the dissolved gas analysis has to be taken into consideration when there is an abnormal indication or when it is time to execute periodic test on it in order to figure out which type of fault that occurred inside the tank. Even though PD signals are very often overlapped by noise pulses, which makes a PD data analysis more difficult for both human experts and for software expert systems, it is required to develop the technology of PD measurement for better effectiveness.