THERMAL MODELING OF PORTABLE POWER-CABLES

The U.S. Bureau of Mines(1) investigated the performance of portable p ower cables under time-varying load conditions. This research had a tw ofold purpose: 1) to define the thermal characteristics of electricall y overloaded trailing cables and 2) to construct a thermal model for c ables to predict cable temperature rises resulting from load currents, Several tasks were undertaken in support of these goals during the th ree-year research effort. Overload tests ranging from 2 to 12 times ra ted ampacity sere conducted in the Pittsburgh Research Center's Mine E lectrical Laboratory. A thermal model of energized type G-GC trailing cables sas constructed based upon empirical data from the U.S. Bureau of Mines load tests This model was then incorporated into an interacti ve computer program that can assist designers and approvers of mining machines in selecting the appropriate size trailing cable, This progra m can be the basis for a cable protection system which ensures that ca bles are not the source of fires, ignitions, burns, or explosions unde rground.