A Study on Calculation of DC Railway Loadflow with Energy Storage System

초록

Due to the recent environmental protection trend which enforces more strict energy savings, every transportation system should reduce energy consumption to the absolute minimum. High-efficiency operation systems, energy saving methods, and CO2 emissions have become vital issues in the railway system, as well as other major public transportation systems. In order to achieve maximum energy savings, installation of the ESS has been considered. 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. By using a new continuous DC railroad powerflow algorithm, the energy saving effects of the storage devices installed in each substation of the Korean railroad system have been analyzed. Loadflow case studies with actual operation conditions for a DC electric railway system have executed to verify whether the energy storage devices give affirmative effect for cost saving. Also, the algorithm can determine the optimized power and storage capacity of the storage devices for the efficiency. In order to verify the storages devices’ effectiveness on the operating conditions of the service line, case studies for 12 lines in Korea have been completed and a quantitative analysis has been performed.