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Investigation of Very Low Frequency Dissipation Factor of the Contaminated Underground Cable Joints
Author(s)
Hengcharoensuk, Tassana
Nupinit, Thanapon
Chusang, Kittidech
Ravangvong, Tanachot
Date Issued
October 25, 2020
Type
Conference Paper
Abstract
This paper presents the characteristics of the contaminated underground cable joints tested by a very low frequency voltage source. The underground cable system used in the experiment was comprised of a 12/20(24) kV underground cable with a cross-section area of 240 mm2, and the length of 6 m. Four different case studies were simulated on the cable joint, i.e., a healthy heat shrink cable joint (case 1), a cable joint with an incision on XLPE surface(case 2), a cable joint contaminated with 20-micron iron powder on XLPE surface(case 3), and a cable joint contaminated with 20-micron copper powder on XLPE surface(case 4). The dielectric dissipation factor, also known as tan δ at very low frequency (0.1Hz) of such underground cable systems, was examined at 0.5 U0, 1 U0, and 1.5 U0, respectively. The very low frequency(VLF) test voltage was applied to the cable specimen, according to IEEE 400.2(2013). The test voltage was recorded and analyzed. It was found that the cable joint contaminated with 20-micron iron powder on XLPE surface had a maximum tan δ. The tan δ value decreased respectively for the cable joint with an incision on XLPE surface and the cable joint contaminated with 20-micron copper powder on XLPE surface. The healthy heat shrink cable joint showed the lowest tan δ. It was clearly shown that the contaminated cable joint caused higher very low frequency tan δ compared with the healthy cable joint.
Citation
Proceeding 8th International Conference on Condition Monitoring and Diagnosis Cmd 2020, 342-345, 2020