153 research outputs found
Energy Management Systems for Smart Electric Railway Networks: A Methodological Review
Energy shortage is one of the major concerns in today’s world. As a consumer of electrical energy, the electric railway system (ERS), due to trains, stations, and commercial users, intakes an enormous amount of electricity. Increasing greenhouse gases (GHG) and CO2 emissions, in addition, have drawn the regard of world leaders as among the most dangerous threats at present; based on research in this field, the transportation sector contributes significantly to this pollution. Railway Energy Management Systems (REMS) are a modern green solution that not only tackle these problems but also, by implementing REMS, electricity can be sold to the grid market. Researchers have been trying to reduce the daily operational costs of smart railway stations, mitigating power quality issues, considering the traction uncertainties and stochastic behavior of Renewable Energy Resources (RERs) and Energy Storage Systems (ESSs), which has a significant impact on total operational cost. In this context, the first main objective of this article is to take a comprehensive review of the literature on REMS and examine closely all the works that have been carried out in this area, and also the REMS architecture and configurations are clarified as well. The secondary objective of this article is to analyze both traditional and modern methods utilized in REMS and conduct a thorough comparison of them. In order to provide a comprehensive analysis in this field, over 120 publications have been compiled, listed, and categorized. The study highlights the potential of leveraging RERs for cost reduction and sustainability. Evaluating factors including speed, simplicity, efficiency, accuracy, and ability to handle stochastic behavior and constraints, the strengths and limitations of each optimization method are elucidated
Hybrid Energy Storage System Taking Advantage of Electric Vehicle Batteries for Recovering Regenerative Braking Energy in Railway Station
Nowadays, nations are moving toward the electrification of the transportation section, and the widespread development of EV charging stations and their infrastructures supplied by the grid would strain the power grid and lead to overload issues in the network. To address this challenge, this paper presents a method for utilizing the braking energy of trains in railway stations to charge EVs located in strategic areas like park-and-ride regions close to railway stations improving energy efficiency and preventing grid overload. To validate the feasibility of the proposed system, a metro substation in Milan city is considered as a case study located in outskirts of the city and contains large number of parking space for vehicles. Three different scenarios are evaluated including DC fast charging station, AC low charging station and collaborative hybrid energy storage based AC charging station as EV charging station type. The results are studied for different EV population number, charging rate and the contractual power grid. Meanwhile, the possibility of proposed system in participating as V2G technology and taking advantage of the EV’s batteries to provide ancillary support to accelerating trains is investigated regarding peak shaving objective. The results indicated that the suggested interconnected system operates effectively when a significant quantity of EVs are parked at the station. However, the results revealed that the performance of the proposed system is notably influenced by other factors and a limited number of EVs during the early morning and late evening periods. Overall, this study confirms the feasibility of energy transfer between two types of transportation means in intermodal areas
Integrating Optimal EV Charging in the Energy Management of Electric Railway Stations
In this paper, an electric railway Energy Management System (EMS) with
integration of an Energy Storage System (ESS), Regenerative Braking Energy
(RBE), and renewable generation is proposed to minimize the daily operating
costs of the railway station while meeting railway and Electric Vehicle (EV)
charging demand. Compared to other railway EMS methods, the proposed approach
integrates an optimal EV charging policy at the railway station to avoid high
power demand due to charging requirements. Specifically, receding horizon
control is leveraged to minimize the daily peak power spent on EV charging. The
numerical study on an actual railway station in Chur, Switzerland shows that
the proposed method that integrates railway demand and optimal EV charging
along with ESS, RBE, and renewable generation can significantly reduce the
average daily operating cost of the railway station over a large number of
different scenarios while ensuring that peak load capacity limits are
respected.Comment: to appear in IEEE PowerTech, Belgrade, Serbia, 202
Opportunities and challenges of power electronics systems in future railway electrification
With the continuous expansion of the railway power
systems, the integration of high speed locomotives and the need to
increase the overhead catenary line power capacity, the main
shortcomings of the conventional railway feeding system are
becoming more evident. In order to overcome these drawbacks
and to contribute to the technological evolution with innovative
and electrically more efficient systems, several solutions have been
proposed and implemented. In this context, this paper briefly
presents a study of different railway power systems, highlighting
emerging concepts, such as regenerative braking, energy storage
systems, the inclusion of renewable energy sources, bidirectional
power flow and wireless power transfer. Some of these concepts
can be implemented in short to medium term, or in the long term.
Following these concepts, an overview of the power electronics
challenges for the implementation of these emerging concepts is
presented and discussed.This work has been supported by FCT –Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020. This work has been supported by the FCT Project QUALITY4POWER PTDC/EEI-EEE/28813/2017. Mr. Luis A. M. Barros is supported by the doctoral scholarship PD/BD/143006/2018 granted by the Portuguese FCT foundation. Mr. Mohamed Tanta was supported by FCT PhD grant with a reference PD/BD/127815/2016
Modeling and Simulation of Regenerative Braking Energy in DC Electric Rail Systems
Regenerative braking energy is the energy produced by a train during
deceleration. When a train decelerates, the motors act as generators and
produce electricity. This energy can be fed back to the third rail and consumed
by other trains accelerating nearby. If there are no nearby trains, this energy
is dumped as heat to avoid over voltage. Regenerative braking energy can be
saved by installing energy storage systems (ESS) and reused later when it is
needed. To find a suitable design, size and placement of energy storage, a good
understanding of this energy is required. The aim of this paper is to model and
simulate regenerative braking energy. The dc electric rail transit system model
introduced in this paper includes trains, substations and rail systems
Analysis, Evaluation and Simulation of Railway Diesel-Electric and Hybrid Units as Distributed Energy Resources
The objective of this paper involves the analysis, identification and evaluation of different possibilities offered by technology for the improvement and the management of the use of energy and hybridization in railways: On board generation, demand response and energy storage, both in traction and auxiliary loads, considering the aggregation of resources and its stochastic nature. The paper takes into account the importance of efficient use of energy in railways, both currently (trains in service, prototypes) and in the future, considering the trends driven by energy policy scenarios (2030–2050) that will affect service and operation of units during their lifetime. A new activity has been considered that will be relevant in the future in the framework of a new electricity
supply paradigm: Smart-Grids. According to this paradigm, the interaction of the Electric Power System and the Railway Supply System (somehow embedded in the Power System) will bring new opportunities for the collaboration of these two systems to perform, in a wise economic fashion, a better and more reliable operation of the complete energy system. The paper is focused on a mixed profile with low-medium traffic (passenger and freight): The first part of the route is electrified (3 kV DC catenary) whereas the second part is not electrified. Results justify that complex policies and objectives bring an opportunity to make cost-effective the hybridization of railway units, especially in low/medium traffic lines, which improves their social and economic sustainability.Authors are very grateful to the information, data and technical discussions provided by Patentes Talgo S.A. (Spain). This work was supported by the Ministerio de Ciencia, Innovación y Universidades (Spanish Government) under research project ENE-2016-78509-C3-2-P; Ministerio de Educación (Spanish Government) under grant FPU17/02753 and especially EU FEDER funds.
This work was supported by the Ministerio de Ciencia, Innovación y Universidades, Spanish Government) under research project ENE-2016-78509-C3-2-P; Ministerio de Educación through grant FPU17/02753 and EU FEDER funds. Authors have also received funds from these grants for covering the costs to publish in open access
SMART SOP ARCHITECTURES AND POWER CONTROL MANAGEMENTS BETWEEN LIGHT DC RAILWAY AND LV DISTRIBUTION NETWORK
This paper presents different architectures of smart soft open points to interface electrified DC railways and low voltage power distribution networks. Both networks have similar objectives of power losses reduction, preserve network stability even with a high penetration of renewable energy sources, and accommodate new energy sectors such as electric vehicles and energy storage systems. The proposed smart soft open points will enable a flexible inter-exchange of electrical power between the two networks in order to achieve these challenging objectives. Different power management control approaches are provided in this paper according to the traffic conditions on the railway network as well as the power and voltage conditions of the distribution network
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