RTS 2010 - Dynamic Load Modelling of Electric Locomotive for Power Quality Assessment of Utilities

The AC 25 kV electric railways with DC drive locomotivesare one of the main harmonic pollution sources of electricpower grids in China. To assess the power quality of therailway supply networks needs to model not only thefundamental currents of the trains but also their harmoniccontents. It is difficult to simulate accurately the dynamiccurrent waveforms of an electric locomotive running on reallines because there are too many random or uncontrolledfactors that can intervene the working state of the main powercircuit of the locomotive. This paper presents a modellingmethod that can imitate the probabilistic property of thecurrent waveform and can embedded in the train simulator.This method is based on statistical analysis of a large amountof measured data of locomotive currents that were acquiredon actual railway line. A computer program has beendeveloped for the 8K locomotive, a kind of widely usedlocomotives for freight services in China. The program hasbeen applied to assess the power quality of railway powersupply utilities, which shows that this modelling method cangive a very realistic result from the statistics point of viewand has a fast speed in the simulation.