Elevated temperature operation of XLPE distribution cable system

Economical operation of modern distribution cable networks requires a detailed knowledge of the thermal effects of higher currents. The authors report on a continuing investigation to determine the maximum emergency and continuous ratings which cables may sustain without impairing operating life. Detailed investigations include the measurement of temperatures at different parts of a cable during heavy current cycling and the resulting mechanical stresses and strains. The reasons for these mechanical forces are explained by considering the differential thermal expansion of the materials used in the cable. Thermally induced torques leading to mechanical failure may be influenced by neutral design