Polypropylene laminated paper (PPLP) insulation for HVDC power cables

Space charge is a major issue that hinders the development of HVDC polymeric cables. On the other hand, HVDC cables with polypropylene laminated paper (PPLP) insulation has been in operation for a long time with a good record. In the present paper, the electrical performance of PPLP insulation has been studied to understand the reasons for its excellent characteristics. It has been found that the charge accumulated at the interface between PP and Kraft paper plays a key role in determining electrical performance of PPLP insulation. The formation of the interfacial charge results in an optimal electric field distribution for PPLP insulation system as well as a small and electric field independent conductivity.