Investigation of grid-connected photovoltaic generation system applied for Urban Rail Transit energy-savings

In the paper, the feasibility and application modes of Photovoltaic (PV) generation system were studied in Urban Rail Transit (URT). Firstly, the paper estimates the capacity of PV cells installation, and gets the results that PV generation system applied in the URT energy-savings is feasible by studying a typical elevated line of Shanghai URT. And then, in view of the particularity of URT power system and its loads, AC grid-connected mode and DC grid-connected mode are presented, and the grid-connected topology and energy management strategy were developed respectively. The results of simulation and theoretical analysis show that the AC grid-connected mode is simple and its control strategy is mature, but it hasn´t energy-savings amplification effect, DC grid-connected mode has energy-savings amplification effect, and can maximize the benefits of PV generation system through the optimization of control strategy. Finally, the key issues in the implementation of DC grid-connected mode were discussed.