Study of trackside photovoltaic power integration into the traction power system of suburban elevated urban rail transit line

Abstract

The trackside of suburban elevated urban rail transit (URT) line is a potential platform for placing Photovoltaic (PV) panels. This paper has made a comprehensive study of trackside PV power integration into the direct current (DC) traction power supply system of URT. With the elevated section of Metro Line 11 in suburban Shanghai as an example, the potential PV installation capacity has been evaluated. Based on the unique feature of the DC traction power supply system, a DC side PV integration scheme and control strategy has been proposed. The simulation models based on the electrical characteristics of URT power system and the moving train have been especially developed as an effective tool to perform the scenario analysis of different PV integration schemes, and an energy saving parameter “k” has been proposed to evaluate the energy saving effect. It concludes that DC side PV integration can help to compensate the traction voltage and reduce the catenary transmission loss in the traction stage of trains, thereby it has a higher energy saving rate. Even better performance can be achieved with both PV and energy storage system (ESS) integrated into the DC traction power system. The energy saving result can achieve the effect of “1 + 1 > 2”, which means the total amount of energy savings is even larger than the sum of PV or ESS working alone. Moreover, the traction power quality and safety will also be improved.