Tan delta and capacitance characteristics of underground XLPE cables – 11 kV

Abstract

There are several appropriate techniques can be used in order to show the characteristics of aged and unaged underground XLPE cables after sometime in service. From the characteristics, performance of the cables can be evaluated. One of the techniques is based on tan delta and capacitance measurements of the cable insulation. This study focuses on underground XLPE cables which rated at 11 kV for both 1-core and 3-core types. Tan delta and capacitance data of underground XLPE cables are obtained using a Schering bridge instrument. The measurements are performed at the temperature about 29oC and 50 Hz power frequency. The analysis of data shows that tan delta values are increased in proportion to the aging factors and voltage stressed. Meanwhile the capacitance values of the cable insulator are increased and decreased in proportion to the aging factors and voltage stressed. Therefore, tan delta and capacitance are the useful parameters for evaluating the quality of underground XLPE cables insulator.