Enhanced Operating Scheme of ESS for DC Transit System

The energy storage system (ESS) used in the DC feeding urban railway system is an equipment that recycles the regenerated energy produced by the railway vehicles as well stabilizing the catenary voltage. This paper proposes an operation algorithm of ESS that allows a more effective use of the equipment. The proposed algorithm includes an advanced line voltage tracker (ALVT), which responds to the fluctuating catenary voltage by tracking it and the supercapacitor voltage tracker (SCVT), which modifies the operating voltage of the supercapacitors to increase the receptivity of power constrained by the rated current of supercapacitors. The feasibility of this algorithm has been tested and verified at the Seocho substation in Seoul Metropolitan Rapid Transit (SMRT) Line.