Energy savings in metro-transit systems: A comparison between operational Italian and Spanish lines

Falvo, Maria Carmen; Sbordone, Danilo; Fernández-Cardador, Antonio; Cucala, Asunción P.; Pecharromán, Ramón Rodríguez; López-López, Álvaro J.

doi:10.1177/0954409714542276

Cited by 21 publications

(10 citation statements)

References 30 publications

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“…Traction current transmitting over sections exists widely when multiple trains run in multiple sections in DC traction power systems. As stated by Lin [16] and Falvo [17], in DC traction power systems, all traction substations and trains are in parallel operation for the connectivity of the catenary and running rails in the whole line. Traction current of an accelerating train comes not only from the traction substations of the section, but also from traction substations in other sections or regenerative braking trains with a long distance.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Rail Potential Based on Power Distribution in DC Traction Power Systems

Zhang

et al. 2016

Energies

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Running rails used as a return conductor and ungrounded scheme have been widely adopted in DC traction power systems. Due to the longitudinal resistance of running rails and insulation resistance of rail-to-ground, there will be a potential rise between running rails and the ground when return current flows through the running rails, which is known as rail potential. At present, abnormal rise of rail potential exists widely in DC traction power systems. The present rail potential model still cannot simulate and explain the abnormal rail potential in the system. Based on the analysis of power distribution with multiple trains running in multiple sections, a dynamic simulation model of rail potential in the whole line is proposed. The dynamic distribution of rail potential and stray current in DC traction power systems when multiple trains run in multiple sections is analyzed, and the impact of traction current distribution on rail potential is evaluated. Simulation results show that the abnormal rise of rail potential during the dynamic operation of the system can be evaluated effectively.

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Section: Introductionmentioning

confidence: 99%

Evaluation of Rail Potential Based on Power Distribution in DC Traction Power Systems

Zhang

et al. 2016

Energies

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“…The energy assessment are based on the following indexes proposed in [40]. These measures make use of figures obtained under different simulation hypothesis.…”

Section: Simulation Resultsmentioning

confidence: 99%

Energy Efficiency and Integration of Urban Electrical Transport Systems: EVs and Metro-Trains of Two Real European Lines

et al. 2019

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Transport is a main source of pollutants in cities, where air quality is a major concern. New transport technologies, such as electric vehicles, and public transport modalities, such as urban railways, have arisen as solutions to this important problem. One of the main difficulties for the adoption of electric vehicles by consumers is the scarcity of a suitable charging infrastructure. The use of the railway power supplies to charge electric vehicle batteries could facilitate the deployment of charging infrastructure in cities. It would reduce the cost because of the use of an existing installation. Furthermore, electric vehicles can use braking energy from trains that was previously wasted in rheostats. This paper presents the results of a collaboration between research teams from University of Rome Sapienza and Comillas Pontifical University. In this work, two real European cases are studied: an Italian metro line and a Spanish metro line. The energy performance of these metro lines and their capacity to charge electric vehicles have been studied by means of detailed simulation tools. Their results have shown that the use of regenerated energy is 98% for short interval of trains in both cases. However, the use of regenerated energy decreases as the train intervals grow. In a daily operation, an important amount of regenerated energy is wasted in the Italian and Spanish case. Using this energy, a significant number of electric vehicles could be charged every day.

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“…The usable regenerated energy that a train can produce depends mainly on two factors: the efficiency ratio of the train motor (that measures the efficiency of the train as a kinetic energy accumulator), and the transmission losses produced at catenary [30,79,80]. For this reason, the influences of different realistic values of these factors are analyzed in this paper to provide insights into the benefits provided by eco-driving on these types of lines.…”

Section: Introductionmentioning

confidence: 99%

Assessment of the Worthwhileness of Efficient Driving in Railway Systems with High-Receptivity Power Supplies

et al. 2020

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Eco-driving is one of the most important strategies for significantly reducing the energy consumption of railways with low investments. It consists of designing a way of driving a train to fulfil a target running time, consuming the minimum amount of energy. Most eco-driving energy savings come from the substitution of some braking periods with coasting periods. Nowadays, modern trains can use regenerative braking to recover the kinetic energy during deceleration phases. Therefore, if the receptivity of the railway system to regenerate energy is high, a question arises: is it worth designing eco-driving speed profiles? This paper assesses the energy benefits that eco-driving can provide in different scenarios to answer this question. Eco-driving is obtained by means of a multi-objective particle swarm optimization algorithm, combined with a detailed train simulator, to obtain realistic results. Eco-driving speed profiles are compared with a standard driving that performs the same running time. Real data from Spanish high-speed lines have been used to analyze the results in two case studies. Stretches fed by 1 × 25 kV and 2 × 25 kV AC power supply systems have been considered, as they present high receptivity to regenerate energy. Furthermore, the variations of the two most important factors that affect the regenerative energy usage have been studied: train motors efficiency ratio and catenary resistance. Results indicate that the greater the catenary resistance, the more advantageous eco-driving is. Similarly, the lower the motor efficiency, the greater the energy savings provided by efficient driving. Despite the differences observed in energy savings, the main conclusion is that eco-driving always provides significant energy savings, even in the case of the most receptive power supply network. Therefore, this paper has demonstrated that efforts in improving regenerated energy usage must not neglect the role of eco-driving in railway efficiency.

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Energy savings in metro-transit systems: A comparison between operational Italian and Spanish lines

Cited by 21 publications

References 30 publications

Evaluation of Rail Potential Based on Power Distribution in DC Traction Power Systems

Evaluation of Rail Potential Based on Power Distribution in DC Traction Power Systems

Energy Efficiency and Integration of Urban Electrical Transport Systems: EVs and Metro-Trains of Two Real European Lines

Assessment of the Worthwhileness of Efficient Driving in Railway Systems with High-Receptivity Power Supplies

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