On-line PD measuring system modeling and experimental verification for covered-conductor overhead distribution lines

In this paper, EMTP/ATP simulation environment is used to model on-line single-phase partial discharge (PD) measuring system using Rogowski coil for the monitoring of falling trees on the covered-conductor (CC) overhead distribution lines. The CC is modeled as a distributed parameters line and Rogowski coil is modeled based on its equivalent circuit as a saturable current transformer having linear magnetizing characteristics. The simulation results are compared with those obtained from the laboratory measurements. The model can be used to estimate the length of the CC line at which PDs due to falling trees can be detected; thus, deciding the number and positioning of the sensors over a particular length of the CC overhead distribution line.