power quality improvement in traction power supply networks

ac railway traction loads are usually huge single phase loads. as a result, a significant amount of negative sequence current (nsc) is injected into utility grid. moreover, harmonics and consumption ofreactive power are further power quality problems that the supply network is encountering. in this paper, acompensation strategy with the aid of railway power conditioner (rpc) is proposed to overcome the abovementionedproblems. firstly, different kinds of traction transformers are evaluated and y/δ tractiontransformer is chosen. then, a compensation strategy is initiated that is valid for all kinds of tractiontransformers and a control system is proposed based on that. finally, the correctness of the analysis andproposed strategy is verified by the simulation results using  matlab/simulink software.