Testing 35kV cable lines type IPZO13 and re-energized after flood damage

Abstract

This paper presents an improved approach to testing the condition of cables in terms of further exploitation. The advantages and disadvantages of using DC and VLF test voltages are noted. A description of two damaged electric power cables in a city is given. The sequence of a realistic possible set of tests is proposed in order to assess the condition of cable insulation. Firstly, the results of the isolation resistance were explained. The results of the testing of capacitance and factor of dielectric losses at the AC 50Hz test voltage are then evaluated. At the end, insulation tests are performed with high DC voltage according to the standard. After switching on the cables, a thermographic test is performed and examples of observed irregularities are shown. In conclusion, the need for simultaneous application of several different test methods and the systematic collection of data on cable insulation is emphasized.

Keywords

• cable line
• insulation resistance
• dielectric loss factor tgδ
• cable capacity
• high voltage DC
• thermographic inspection