Rail transit chopper traction interference modeling using the SPICE circuit simulation package

The application of SPICE to a rail traction network for the simulation of electromagnetic noise emissions and cab signal interference in a DC-fed rail rapid transit system is described. The predictions are validated by a laboratory experiment in which real-time signals are generated by computer using a programmable read-only memory (PROM) lookup table. The simulator can be used to study interference in rail rapid transit systems at low and audio frequencies produced by the combined effects of conduction, magnetic induction, and electric induction. Its use permits the influence of such variables as train position, power demand, and traction duty cycle on interference in cab signaling, track circuit, and other critical noise receivers to be determined. The effect of varying simulation parameters-for example, track impedance-can also be evaluated and parameters strongly influencing the degree of interference identified. The method can also be used to evaluate interference characteristics of new propulsion drives