Pipe-type cable losses for balanced and unbalanced currents

Computations of pipe eddy-current losses have been undertaken for balanced and unbalanced current using a program for transient nonlinear finite element analysis developed by one of the authors. Good agreement is obtained with experimental data from the literature. The computations indicate that the eddy-current losses reach a minimum around 700 A conductor current. Experimental data are available only to about 800 A so that this phenomenon has not been reported previously and may have an impact on rated ampacities for high-pressure fluid-filled (HPFF) cable. Computations for unbalanced currents indicate increased losses with increasing unbalance, as expected.