Thermal modelling and experimental validation for research on medium voltage DC cables

The thermal behavior of medium voltage dc cables can find useful applications for efficient and capacity enhanced operation in cities as well as compact power transmission on all electric ships. Concepts such as dynamic current and voltage rating, difference in thermal proximity in ac and dc operation, pulsed load application and thermal degradation with enhanced dc voltage; all are interlaced with the crucial temperature profile of insulated conductors. This paper develops a theoretical thermal model to highlight the possibility of dynamic current rating with pulsed loads. Further, a novel idea of imposing a thermal profile on cables for dc partial discharge testing is discussed. For this purpose a heat transfer model for a segmented cable is developed and experimentally validated.