Challenges of partial discharge diagnostics of low-voltage cables

Partial discharge measurement is one of the most important diagnostic methods to detect local faults in insulation systems. Detection of local faults in low-voltage cables would be attractive for condition assessment of power plant secondary cables. The construction of low-voltage cables is different from the medium and high voltage ones, preventing the direct application of the already developed models and methods. An analysis of partial discharge detection and evaluation methods for low-voltage cable diagnostics are given in this paper. Some laboratory measurement results are also presented and the identified issues are described in this paper.

► PD are not a root cause for failures of low-voltage cables.
► PD do incept at their test voltage even in brand new condition.
► A major identified complication is the large number of discharge sites in the cables.
► Wide-band methods are necessary to detect PD in low-voltage cables.
► Parameters exhibiting changes were found when new and faulty cables were compared.