Techno-economic Sizing of Auxiliary-Battery-Based Substations in DC Railway Systems

Modeling, Simulationand Analysis of On-Board Hybrid Energy Storage Systems for Railway Applications

“…Similar conclusions were obtained in [26]; in this work, the use of wayside energy storage improved the overall efficiency by more than 20% and also improved the controllability and the voltage profile of the network. Similar conclusions were obtained in [24,27] supporting the previous conclusions. In [24], the use of energy storage at the substation level reduced the annual cost of energy by 13%.…”

“…Similar conclusions were obtained in [24,27] supporting the previous conclusions. In [24], the use of energy storage at the substation level reduced the annual cost of energy by 13%. We would like to point out that the main contribution of this paper is the mathematical model; a detailed comparison between the infrastructure alternatives considering wayside and on-board energy storage and reversible substations is beyond the scope of the work, which is focused specifically on providing an accurate and efficient model to simulate on-board energy'storage.…”

“…An accurate sizing of all the elements in the system was critical for a proper energy management within the system [21][22][23]. In other cases, the storage systems were installed off-board at the substation level [24]. Many applications, like the one presented in this paper, use hybrid energy storage systems based on batteries and ultracapacitors; usually, the battery covers a base load, and the ultracapacitors are used for feeding the peak power.…”

A Preliminary Techno-Economic Comparison between DC Electrification and Trains with On-Board Energy Storage Systems

“…where R a and R b are expressed in [Ω], ρ [Ω/km] represents the resistive coefficient, d [km] is the distance between the two nodes (upstream and downstream the train). In order to improve the train electric model, describing the receptivity of the network under regenerative braking conditions, a small capacitance is connected in parallel to current source that represents the vehicle [46]. In Figure 2 it is shown the electric model of the overall railway system, one side supplied contact line.…”

“…Energies 2020, 13, x 5 of 27 where , and are the coefficients of the Davis formula, related to the train and track characteristics, and they can be estimated by empirical measures; g is the gravitational acceleration and ( ) is the slope grade. The second term of RTRACK is the curve resistance given by empirical formulas, as the Von Röckl's formula, where ( ) is the curvature radius, and a, b are coefficients which depend on the track gauge; in this paper it is considered a = 0.65 m and b = 55 m [46].…”