PARTIAL DISCHARGE LOCATION IN TRANSFORMER WINDING USING CORRELATION TECHNIQUE

Abstract

In a power system network, power transformer plays a very important role in maintaining the constant system operating voltage throughout its long service life. Partial discharge (PD) is one of the major reasons for failure of insulation in HV transformers. The PD source is very much random in nature. Hence, the information of the PD source locations is significant for reducing the deterioration of transformer and its winding. Because of the complex structure of the transformer winding, it is very complicated to locate the PD accurately in transformer winding. Correlation techniques are applied to locate the PD source across the winding. The PD across the sections of the winding is simulated by applying voltage pulse across the sections. The winding response for a reference PD impulse across transformer sections are taken as base for correlation and they are further correlated with winding response of PD impulse across any section with different PD pulse widths. The time domain correlation method has a disadvantage that it fails when reference and test pulse widths are different. So, in the thesis to overcome the drawback of time domain correlation technique, frequency domain correlation is used along with Grain Schmidt orthogonalization process. Simulation is carried out for a six section transformer winding using different test pulse widths.