Partial Discharge Measurement for Condition Assessment of High Voltage Cables in Power System

Abstract

To achieve high supply reliability in power system, ensuring high voltage cables in healthy and operational condition in transmission system is a prerequisite. Assessing the health condition of high voltage cables is a crucial task to prevent system fault. Traditionally, the sound condition of high voltage cables is proven by high voltage testing before commissioning. However, high voltage testing may not reveal all defects on the cable or even developing new defect. Various condition monitoring methodologies have been implemented on power transformer and gas-insulated switchgear for real time condition monitoring. Nevertheless, condition monitoring on cross-linked polyethylene (XLPE) cables is still challenging. We have developed a solution to assess the insulation condition of energised XLPE cable by partial discharge (PD) measurement using high frequency current transformer (HFCT) through link-boxes. The insulation condition can be diagnosed by (phase-resolved PD) PRPD pattern, and source of PD can be traced from the frequency of PD impulse. The effectiveness of PD measurement by HFCT is demonstrated by real cases.