Electrical and Thermal Analysis of Parallel Single-Conductor Cable Installations

The unequal current distribution in parallel single-conductor cable installations can lead to an excessive temperature rise. This paper presented a cable model and a procedure of coupled electrical and thermal analysis for the evaluation of currents, losses and temperatures in the cables of concern. The cable model and analytic method were validated experimentally in the laboratory. The procedure was applied to evaluate the current rating, the temperature rise in a particular single-conductor installation. It is concluded that the parallel cable installation without proper cable rephrasing de-rates the cables significantly. The 3^rd order harmonic current can cause a significant reduction of the current rating if its distortion is over 30%.