XLPE INSULATED HIGH VOLTAGE UNDERGROUND CABLE ASSESSMENT BY LEAKAGE CURRENT STUDIES

Abstract

The leakage current characteristic of high voltage underground cable was studied in this research. It is quite useful to assess the status of insulation after using for a while. This is an important data to do a decision making to prolong its lifetime or replacement a new one. A study was taken with the simulation circuit established from each none breakdown failure in XLPE insulated high voltage underground cable such as water treeing, electrical treeing, partial discharge, aging according to usage and surface leakage current along the cable’s accessories, etc. This study was performed with Proteus 8.0 on single phase cable with variation of voltage and frequency. The results of leakage current from each case were compared with a healthy cable in order to establish a specific tendency characteristic. These characteristics were used to be a tool to classify the failure type in the insulation. Moreover, an analytical tool was developed with Excel@ in order to evaluate the status of an insulation with failure type (if any) from the change behavior of leakage current and phase angle. This was done by comparison the leakage currents obtained from each cable in a three-phase cable system with has a same construction and length. The simulation of leakage current data from a three-phase cable system integrated with any failure type in any phase in random was putted in to the developing tool. The obtained result could be determined correctly both in the failure phase and failure type.