Energy Saving Study of Mass Rapid Transit by Optimal Train Coasting Operation

Abstract

This paper presents a movement of electric train between two-passenger stopping stations with the goal of minimized total energy consumption during the journey. A train movement is based on a sequence of four operation modes: i) accelerating mode, ii) constant speed or cruising mode, iii) coasting mode and iv) braking mode. The optimization problem in which the train speed profile is optimized by controlling of three parameters: i) acceleration rate ii) deceleration rate and iii) location of coasting point. By using Quadratic Search Method (QDS) which is a mathematical method to calculate the optimal location of the coasting point, with the goal of using the minimum energy consumption and no effects with the train movement and the operating time of the train services. The case study applied in this paper is a mass rapid transit system which travels between two passenger stations with a service distance of 1 km and a maximum speed of 45 km/h. The results showed that the longer distance of the coasting mode the less power consumption in the cruising mode and the less power from the brake mode. On the other hand, the short distance of the coasting mode the more power in cruising mode and the more power from the brake mode. It is found that the optimal location of the coasting point obtained by QDS is considerably capable to reduce the overall energy consumption by 3.8%.