The Cooling of Underground EHV Transmission Cables

Proposed cable cooling methods to increase the heat dissipation and rating of underground EHV cables are described. The factors governing the design of water cooled cable systems, obtained from an electrical analog, are presented and discussed together with both steady-state and transient operating conditions. Special cooling methods for cable joints are investigated and modifications to construction suggested. The use of special types of cable with enhanced heat transfer properties is considered.