PROXIMITY EFFECT AND EDDY-CURRENT LOSSES IN INSULATED CABLES

Insulated cables are generally designed according to thermal criteria : the current rating depends on the permissible temperature inside the insulation. As the heating of a cable mainly results from Joule losse s, it is worthy to determine the current distribution in its metallic components (the core and the metallic screen for single core cables). The current distribution in cables is affected by the skin effect and the proximity effect due to neighbouring cables of the circuit itself or from parallel links. A general method is developed to calculate the current distribution in the core and the screen of a single-core cabl e, starting from Maxwell equations. The stress is set upon skin and pr oximity effects, taking into account the influence of the frequency. J oule losses are calculated in some practical cases of three-phase link s.