Partial discharge diagnosis of ceramic pin insulators considering cost-worth analysis: Case study in a medium voltage feeder

Power distribution networks have extensive and long length medium voltage (MV) feeders due to direct contact with the customer. Network extension will be followed by an increase in the number of installed insulators. Pin ceramic insulators cause various problems for the operation of the distribution network because they are made of two-piece (TP). The expansion and contraction of cementitious material between two pieces of insulators create some defects for poor quality of production and critical conditions of insulation problem for these insulators. In this paper, the ultrasonic diagnosis method based on monitoring of partial discharge (PD) signals of TP pin ceramic insulators have been studied and the leakage losses of these insulators in network conditions for a MV feeder of North Khorasan Electrical Distribution Company (NKEDC), called Khanloq feeder, were calculated. Finally, the economic consideration of a sample project of insulator replacement and estimating the project investment return for Khanloq feeder by using PD signals analysis have been discussed.