Field Experience in Application of Polarisation Depolarisation Current (PDC) In High Voltage (HV) Equipments – A Review

Abstract

Insulation diagnosis is important to High Voltage Equipment such as transformer, power cable and rotating machine. Conventional methods such as Insulation Resistance (IR) and Dielectric Dissipation Factor (DDF) have been part of the diagnostic testing for the last decade. Although these methods are useful in determining the general condition of the insulation, nevertheless isolating the causes of the deterioration of insulation require more detail analysis. The analysis includes the behavior or responses of the insulation under static or varying electric field. In this paper, the author will review one of the technique called polarization depolarization current (PDC) that will look into the dielectric responses under static electric field (DC) in order to diagnose the condition of various high voltage equipment such as power cable, transformer and rotating machine. Theory on the technique will be explained in the beginning, followed by parameters used by other authors in evaluating the condition of insulator. Finally, the author will share three case studies that based on field experience in determining the condition of insulation for rotating machine, transformer and power cable using PDC technique.