Peak Power Demand and Energy Consumption Reduction Strategies for Trains under Moving Block Signalling System

Qing Gu,Yongduan Song,Tao Tang,Fang Cao,Hamid Reza Karimi

doi:10.1155/2013/940936

Abstract

In the moving block signalling (MBS) system where the tracking target point of the following train is moving forward with its leading train, overload of the substations occurs when a dense queue of trains starts (or restarts) in very close distance interval. This is the peak power demand problem. Several methods have been attempted in the literature to deal with this problem through changing train’s operation strategies. However, most existing approaches reduce the service quality. In this paper, two novel approaches—“Service Headway Braking” (SHB) and “Extending Stopping Distance Interval” (ESDI)—are proposed according to available and unavailable extra station dwell times, respectively. In these two methods, the restarting times of the trains are staggered and traction periods are reduced, which lead to the reduction of peak power demand and energy consumption. Energy efficient control switching points are seen as the decision parameters. Nonlinear programming method is used to model the process. Simulation results indicate that, compared with ARL, peak power demands are reduced by 40% and 20% by applying SHB and ESDI without any arrival time delay, respectively. At the same time, energy consumptions are also reduced by 77% and 50% by applying SHB and ESDI, respectively.

Highlights

Moving block signalling (MBS) [1] was proposed a few decades ago to reduce headway among successive trains in a track line
Two successive trains are separated by a short distance, which is equivalent to the braking distance of the following train from its current speed, as well as a safety margin
The advantages of Extending Stopping Distance Interval (ESDI) are still obvious, because it is more efficient on energy saving; it can reduce energy consumption by 50% compared with graded acceleration rate limit (ARL) technique

Summary

Introduction

Moving block signalling (MBS) [1] was proposed a few decades ago to reduce headway among successive trains in a track line. Advanced control and manufacturing technology improve the stability, capacity, and weight of ESS [2,3,4,5], which makes it suitable to be equipped in the substations or in trains It could store the regenerative braking energy and assist the main power source during train’s acceleration period. The existing techniques can reduce peak power demand at different degrees, they increase the travel time between the successive stations and decrease the service quality. Considering energy saving driving strategy could be seen as a kind of driving mode switching process [13,14,15,16]; a nonlinear programming model is contributed and the simulation results show that, compared with the best traditional PDR techniques, both of these two methods could reduce the peak power demand and energy consumption without any arrival time delay increasing. When the available extra station dwell time is the same as the unavailable extra station dwell time, SHB performs better than ESDI since more peak power and energy consumption could be reduced

Tracking Dynamics and Peak Power Demand in MBS

Peak Demand Reduction Techniques

Findings

Simulation and Discussion

Conclusion