Criteria influencing the selection and design of HV and UHV DC cables in new network applications

This study sets out to discuss the challenges that need to be addressed effectively to facilitate the adoption of long distance high-voltage and ultra-high-voltage direct current (UHVDC) power transmission cables. As in the alternating current case, the desire to minimise the losses has involved the use of increasingly high transmission voltages, which presents particular problems where UHVDC cables are concerned. Specifically, this study presents the case for a novel, integrated approach to the problem, which links three distinct aspects of the problem, namely: (i) cable ratings and network operability; (ii) cable design and constituent insulating material requirements; and (iii) potential strategies for the design of novel insulation materials, where the required properties are actively ‘designed in’. The study concludes that the impact of these factors acting in concert on network operation/performance requires a more integrated approach to the problem than has traditionally been the case. A number of complementary strategies for the development of novel material technologies and UHVDC cable designs are required that can meet the service performance and ultimate service lifetimes expected for new network applications.