Grounding and electromagnetic analysis of conduit enclosed electric distribution systems

A new modeling method for the analysis of conduit enclosed electric circuits is presented. The model permits the computation of the magnetic field around the circuit and the apparent impedance of the circuit as a function of the electric current. The nonuniform magnetic saturation of the steel conduit is accurately predicted. The conduit enclosed circuit model has been integrated into a network solver, which is capable of simulating power distribution systems with any number of embedded conduit enclosed circuits and other devices. This approach allows performance evaluation of conduit-enclosed circuits, taking into account the interactions with the overall electric power system. Several types of conduit materials can be simulated, including electrical metallic tubing (EMT), intermediate metal conduit (IMC), galvanized rigid conduit (GRC), aluminum conduit (ARC) as well as nonconductive conduit (for example PVC). The model has been validated with a series of laboratory tests.