Polarization and Depolarization Current Measurement of Underground Cable with Different Cable lengths, Temperatures and Test Voltages

Abstract

This paper represents the polarization and depolarization current (PDC) measurement of 12/20(24) kV XLPE power cable with different cable lengths, cable dimensions, temperatures and test voltages. In experiment 1, the XLPE cable with 5 m long and cross section of 240 mm2 was prepared for (Case V1) investigation. Moreover, two of 2.5 m cables connected by the pre-molded joint (Case V2) was also prepared. In the experiment 1, the PDC experiment was investigated with different step DC test voltages i.e., 500V, 750V and 1,000V respectively. Besides, the dielectric response of underground cables with the length of 15 cm with cross section of 185 mm2 and the lengths of 2.5 m and 5 m with cross section of 240 mm2 including the length of 100 m with cross section of 70 mm2 were prepared for experiment 2. To investigate the effect of temperatures on dielectric response, the cable specimen with the length of 15 cm with cross section of 185 mm2 was set up under ambient temperatures of 30, 50, 70 and 90 degree Celsius for PDC measurement in experiment 3. PDC test results obtained from the experiments were compared. Then the dielectric parameters for PDC experiment such as charge difference analysis, capacitance ratio analysis, and polarization loss factor were analyzed and reported in this paper.