A Dual-Stage Modeling and Optimization Framework for Wayside Energy Storage in Electric Rail Transit Systems

Abstract

In this paper, a dual-stage modeling and optimization framework has been developed to obtain an optimal combination and size of wayside energy storage systems (WESSs) for application in DC rail transportation. Energy storage technologies may consist of a standalone battery, a standalone supercapacitor, a standalone flywheel, or a combination of these. Results from the dual-stage modeling and optimization process have been utilized for deducing an application-specific composition of type and size of the WESSs. These applications consist of different percentages of energy saving due to regenerative braking, voltage regulation, peak demand reduction, estimated payback period, and system resiliency. In the first stage, sizes of the ESSs have been estimated using developed detailed mathematical models, and optimized using the Genetic Algorithm (GA). In the second stage, the respective sizes of ESSs are simulated by developing an all-inclusive model of the transit system, ESS and ESS management system (EMS) in MATLAB/Simulink. The mathematical modeling provides initial recommendations for the sizes from a large search space. However, the dynamic simulation contributes to the optimization by highlighting the transit system constraints and practical limitations of ESSs, which impose bounds on the maximum energy that can be captured from decelerating trains.

Present and Future of Supercapacitor Technology Applied to Powertrains, Renewable Generation and Grid Connection Applications

“…Figure 6 There are several researchers that describe the use of SCs in this type of Dutta, O. [29] proposed a mathematical optimization methodology and a model There are several researchers that describe the use of SCs in this type of vehicle. Dutta, O.…”

“…Dutta, O. [29] proposed a mathematical optimization methodology and a model of a stationary storage systemfor a DC rail transportation application, New York City Transit (NYCT). In this study different technologies are compared, including batteries, flywheels and SCs working independently or together.…”

Development of Strategies to Prevent Third Rail Insulator Failures in Transit Systems

“…Third rail operational cost is less than diesel or steam locomotives, and they are more environmentally friendly [30,31]. The main advantage of third rails over the overhead wires is that they do not require construction to be conducted through the train path, which leads to lower costs [32,33].…”

“…Little visual intrusion on the environment [30] Less expensive installment procedure [30] No vertical clearance required [33] More robust than overhead line systems [32,35] Easy to reach and easy to maintain [31] Third rail disadvantages Speed limitation [29] Involves safety hazard [34] Limited capacity due to the low voltage [27] High voltage drop [4] Cannot be used for freight and high-speed trains [28] short-circuit power is low enough [11]. Supply voltage distortion, which is common in electrical systems that use capacitors, can be boosted by parallel resonances.…”