Analysis for EDLC Application on Electric Railway System

초록

Six thousands of vehicles are operated on Korean urban transit system. 95% of them have regeneration system. Especially, the VVVF-Inverter vehicle has a merit of the highest regeneration rate. Energy consumption is 90% for traction and 10% for auxiliary supply. Braking energy is 40% of energy consumption. Up to 40% of the tractive power of vehicles capable of returning energy to the power supply can be regenerated during braking and that this energy can be used to feed vehicles which are accelerating at the same time. The energy generated by braking vehicle would simply be converted into waste heat by its braking resistors if no other vehicle is accelerating at exactly the same time. Such synchronized braking and accelerating can not be coordinated, the energy storage system stores the energy generated during braking and discharges it again when a vehicle accelerates. The energy storage system creates optimum conditions for energy regeneration in urban mass transit system. The energy storage system is able to store and discharge energy extremely quickly, consequently enabling a complete exchange of energy between vehicles, even if they are not braking and accelerating at precisely the same time, as is most frequently the case in everyday service. The energy storage system reduces primary energy consumption without affecting transport capacity and punctuality. In addition, the energy storage units can stabilize the system voltage. The energy storage system is needed to be developed to use regeneration energy when the vehicle is braking. The electric double layer capacitor(EDLC) is applied as the energy storage system. The cost-effectiveness is reviewed about this system on Korean urban transit system. These braking energies are converted into costs per day and year. This paper presents the application of the energy storage system on the Korean urban transit system.