Interface tailoring for charge injection mitigation in insulators: Different principles and achievements

Charge build-up in bulk insulation is one of the issues met in the development of materials for HVDC technologies. Progresses have been done for improving polymeric insulators, limiting charge build-up due to intrinsic processes. But margins of progress seem to be available by acting on the mitigation of charger generation at interfaces provided processes at play are well understood. In this contribution, we investigated different routes for tailoring the interface between electrode and polyethylene material, based on chemical modification of the insulation or layer intercalation. Three processes were tested, going from grafting of polar groups, thick nanocomposite layer intercalation up to thin nanocomposite layer deposition. Depending on the process, charge injection control is achieved either for negative charges or for charges of both polarities. The process of charge injection control is discussed with reference to the chemical/physical modifications brought about by the different treatments. The results provide indication towards a strategy to control the charge injection in power cables and other electrical components.