Localization of partial discharge in a transformer winding using frequency response assurance criterion and LMS adaptive filter

Abstract

Transformers are one of the essential and costly pieces of equipment in power grids. Monitoring and detecting insulation faults in transformers at the shortest time helps prevent catastrophic failures. Partial discharge (PD) is one of the most significant insulation failures in power transformers. Due to the complex structures of the windings, the accurate location of a PD source is very difficult to determine. In this paper, a technique based on a frequency response assurance criterion (FRAC) is proposed to determine the location of a PD source in a transformer winding. The responses of the winding to the proposed Heidler function injected in parallel to all sections of the winding are considered as PD reference signals. Moreover, the winding responses of any arbitrary PD pulses applied along the various sections of the winding, are considered as PD test signals. The maximum FRAC value between the reference signals and test signal specifies the location of the PD source. The simulation case studies clarify the superior performance of the proposed method. A least mean square (LMS) adaptive filter is suggested to minimize background noise effects and increase the accuracy of the method. Finally, the proposed method is validated with a laboratory winding.