Study on Location Accuracy of Partial Discharge Locator

Abstract

At joint and terminal sections of the cross-linked polyethylene (XLPE) cable, partial discharges (PDs) occur in defects of insulating materials. The PD generation can occur at any points in the insulation system where electric field strength exceeds a PD inception electric field and can develop until breakdown occurs. That is, PDs which are owing to local electrical stress in the insulation or on the surface of the insulation reflect a kind of sign of insulation deterioration. Therefore, PD measurement is a useful technique of assessing the insulation deterioration of XLPE cables. For conventional systems to measure and locate PDs, the propagation velocity of PD pulse must be known. However, it likely depends on the aging deterioration of power cable and the number of joint sections. We therefore propose a partial discharge locator (PDL) system which has a time synchronization measure and a unique time generation measure based on LabVIEW. The PDL is possible to locate a PD occurrence position without power interruption. We here show how the PDL works with a time synchronization between detecting devices arranged at both sides of an XPLE cable to be measured. Additionally, it is investigated that the PD-position locating accuracy is within 10 %.