This project aims to develop tools for the rating and technical assessment of high power HVDC cable systems with mass impregnated insulation. The calculation of current ratings for DC cable is significantly more complex than that for AC cable. The rating is often determined by electric stress constraints rather than considerations of thermal ageing. Ratings are also strongly influenced by thermally induced pressure transients within the cable. In some cases the rating of the cable can be restricted by the cable being too cold, requiring different calculation approaches to AC cable where the main criterion is the maximum conductor temperature.
The project intends to develop a comprehensive framework for the rating of HVDC MI cable circuits, making use of techniques such as multiphysics modelling to examine the complex interactions of thermal and electrical stresses. The modelling of transient thermal conditions and the behaviour of the cable insulation under reversals of power flow will provide guidance for the development of dynamic rating algorithms and operational regimes suitable for high power HVDC cable circuits. Consideration will also be given to the effects of polarity reversals to ensure that the best use can be made of HVDC network links in the future.