Computer Simulation for Determining Step and Touch Potentials Resulting from Faults or Open Neutrals in Urd Cable

A computer simulation is described which enables the determination of voltages on the surface and within the earth caused by: (1) a phase-to- neutral fault, (2) a fault with simultaneous open neutrals on either side, and (3) an open neutral. The buried cable and associated ground rods are modeled as a set of interconnected cylindrical segments situated in a three-dimensional, two-layered earth model. Simultaneous solution of the interconnected segment circuit and electromagnetostatic equations yields the desired solution. Output from the computer simulation is shown to match closely the data from field tests of faulted cables and other results from the literature. Work supported by EPRI contract RP797-1.