A Study on Application of Waste Energy from Electric Train

초록

The Korean government proposed the goal of cutting greenhouse gas emissions by 21-30 percent by 2020, relative to the ``business as usual'' (BAU) scenario. The government plans to reduce carbon emissions by the transport sector by 33-37 percent by 2020. The government also pushes ahead with developing eco-friendly transportation systems like recycling energy. Therefore, urban transit operating companies should introduce the energy storage system to save energy cost as a realistic measure[1]. The power system in the railway substation converts AC 22.9kV to DC 1500V. The power system having 12-pulse forward diode rectifiers injects DC power into the catenary. Due to the forward diode rectifiers, regenerative energy doesn’t go back to power utility company. Therefore, the catenary voltage is fluctuated. The electrical equipments are broken down by fluctuated catenary voltage. 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 ESS(energy storage system, here after) stores the energy generated during braking and discharges it again when a vehicle accelerates. The ESS 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[2]. This paper presents the development of the ESS for DC system