A Regenerative Braking Model to Predict the Energy Efficiency Improvement of Railway Electrification: A Case Study in Sri Lanka

With a prevailing population growth rate of 1.5% per annum in Colombo Metropolitan Region, improvement of public transportation has become a vital necessity while optimizing the expenditure on hydrocarbon fuels. Presently, Sri Lanka railway transportation system occupies Diesel Multiple Units (DMU). If Electrical Multiple Units (EMU)with regenerative braking are to be employed in place of DMUs, energy can be regenerated by converting kinetic energy of moving EMUs. This research study initially focused at developing a generalized regenerative breaking model to investigate the electrical energy requirement to travel from one railway station to another and thereby how much electrical energy that could be generated using regenerative braking. Model is then checked and validated with internationally accepted norms developed for efficiency improvement figures. Subsequently, the model is simulated between Colombo Fort and Veyangoda railway stations and found that 457.86 kWh of electrical energy can be saved in one trip through regenerative breaking.