Modelling of rail potential rise and leakage current in DC rail transit systems

In evaluating the rail potential rise and leakage current in DC powered electric railway lines, classical transmission line equations are limited to solving cases with uniform parameters. The circuit approach is more effective for modelling different and complicated situations. A finite cell model of a transmission line under shunt energization at multiple points has been developed for this purpose. It is demonstrated that reasonably accurate results can be obtained if the finite cells are electrically `short´. This finite cell approach, elaborated to represent many parallel conductors, forms the basis of a systematic approach to the representation of the highly complicated situations that arise in with real DC stray currents