Optimal deployment of energy storage systems in a DC-electrified railway system

Abstract

Energy Storage Systems (ESSs) represent one of the main vectors for improving railway electrical systems. Former low reliability rates and life-time are being dramatically improved in recent times due to the intensive research on battery and capacitor technologies. However, little research has been conducted on the optimization of railway system infrastructure by incorporating ESSs. This paper presents a method for designing the best possible deployment of ESSs in a DCelectrified mass rapid transport system line by means of optimization, selecting number and location of ESSs. A detailed model of system load flow and energy storage devices for a given traffic scenario in a general DC railway system has been carried out, resulting in a MINLP optimisation model that minimises total energy consumption. Then, a linearization of load flow equations has been performed in order to get a fast-approximate solution of the system by converting the MINLP problem into a MIP one. This optimization method has been applied to a realistic railway system, yielding reasonable location and number of ESSs in the system. The error due to the approximation has been evaluated by comparing the results of the linear load flow against those of the non-linear load flow. The method has demonstrated to be a powerful tool to decide how many and where to place ESSs in a DC-electrified railway system.

Technical and economic feasibility of increasing tram system efficiency with EV batteries

“…Conversely, a system with a substation that uses separate catenaries/cables to power the uplink and downlink is referred to as a 'separate OCS'. The light-rail or tram network studied in Morita et al (2008), Chymera et al (2010), Hirano et al (2015), and Tian et al (2016) are separate OCS, and the ones in Açikbaş and Söylemez (2007), López-López et al (2012) and Teymourfar et al (2012) are common OCS. The key difference between these two system configurations is that the common OCS allows energy transfer and exchange between uplink and downlink, whereas the separate OCS does not.…”

An electromechanical moving load fixed node position and fixed node number railway power supply systems optimization model

“…Present-day models (Shiokawa and Tagaki, 2012;López-López et al, 2012;Ciccarelli et al, 2012) often consider catenary voltage levels and train speeds for determining the optimal operation of energy storage equipment.…”

Optimal power flow with storage in DC electrified railways

“…(Pankovits et al, 2013) presents a methodology for the design of hybrid railway feeding substations including storage systems and renewable energy, with a local approach. (López-López et al, 2012) introduces a Mixed Integer Programming formulation of an optimization problem aiming to minimize the energy consumption of a DC-Electrified railway using storage systems, including a load flow of the network. Their linearization of the load flow is consistent with their application, but it cannot meet our requirements.…”