Polymer Composites With High Thermal Conductivity for HVDC Cable Insulation: A Review

With the development of high-voltage direct current (HVdc) transmission technology, the voltage level and transmission capacity of power cable need to be further improved. Joule heat originating from the current in the cable conductor brings a great challenge to extruded cable insulation because of the low thermal conductivity of polymer insulation materials. This article reviews the harms caused by heat accumulation in cable insulation and methods for improving the thermal conductivity of polymer materials. First, the effects of heat on cable insulation are summarized. Second, the mechanism, influencing factors, and structure design of filler-based polymer composites with high thermal conductivity are introduced. Subsequently, investigations on cable insulation materials with enhanced thermal conductivity are reviewed. Finally, some problems with the design of thermal conductive networks in semicrystalline polymer materials are discussed, and our suggestions for future work are proposed.