Analysis and Characterization of Partial Discharge Signals From Instrument Transformer in Noisy Environment

Abstract

Partial Discharge (PD) detection is one of the important methods used to evaluate the insulation condition of in-services high voltage electrical equipment. On-site PD detection methods are preferable compared to others method because non-intrusive sensors are easy to install and have no interruptions on operation. An electrical PD testing utilizing High Frequency Current Transformer (HFCT) installed at the ground terminal of the instrument transformer was used to detect partial discharge activities. However, the limitation of this method is the measurement often lacks of accuracy due to interference in PD. The PD signals are hard to distinguish from the stochastic noise pulses. Therefore, the characteristics of PD signals and interferences signals are studied in Phase Resolved Partial Discharge (PRPD) pattern in order to identify the extent of PD signals.