EHV cable systems-a balanced view

As new dielectric systems are developed there is an increasing choice of underground power cable type for EHV applications. This paper considers the three types of single core cable now available for high power applications at system voltages of 400 kV and above: (1) fluid filled paper insulated cable; (2) fluid filled polypropylene paper laminate insulated cable; and (3) solid polymeric insulated cable. Consideration is given to key aspects of EHV cable design and the choice of manufacturing plant required to achieve the necessary insulation quality. These aspects include features common to each type of cable, such as the need for large conductors, high insulation design stresses and metallic sheaths. A performance comparison is made between the three cable types based upon their current ratings.