Time-Domain Modeling of Transmission Line Crossing Using Electromagnetic Scattering Theory

Classical multiconductor transmission line (MTL) theory, which is employed in electromagnetic transient (EMT) simulators, is built on the assumptions that the wire structure is infinitely long and has a uniform cross-section. Therefore, non-uniformities which occur in physical power systems, such as transmission line crossings, are not represented in classical MTL models. A new transmission line model has been developed to calculate space varying per unit length (PUL) parameter matrices near a conductor crossing using electromagnetic scattering theory. The proposed scattered field transmission line (SFTL) model has been implemented for lossless, frequency-independent conductors, that cross each other at a variable crossing angle. A single dimensional finite difference time domain (1D-FDTD) algorithm has been used to obtain the time-domain solution at each simulation time-step. Obtained results have been compared with those from a three dimensional (3D) full-wave electromagnetic solver.