Coupling Mechanisms for PD in MV Cables

The mechanisms by which partial discharges (PD) couple with cable systems have been investigated for both internal and surface PD sources. The results indicate that surface PD are more effective than internal PD in transferring energy to the cable and detector systems. This phenomenon is more marked at frequencies of some hundreds of MHz, implying that antennas can be effective couplers provided that their geometry and electronics are matched with cable radiation patterns and the detection point is very close to the PD source.