Optimized Sizing and Scheduling of Hybrid Energy Storage Systems for High-Speed Railway Traction Substations

Abstract

Abstract:The integration of hybrid energy storage systems (HESS) in alternating current (AC) electrified railway systems is attracting widespread interest. However, little attention has been paid to the interaction of optimal size and daily dispatch of HESS within the entire project period. Therefore, a novel bi-level model of railway traction substation energy management (RTSEM) system is developed, which includes a slave level of diurnal HESS dispatch and a master level of HESS sizing. The slave level is formulated as a mixed integer linear programming (MILP) model by coordinating HESS, traction load, regenerative braking energy and renewable energy. As for the master level model, comprehensive cost study within the project period is conducted, with batteries degradation and replacement cost taken into account. Grey wolf optimization technique with embedded CPLEX solver is utilized to solve this RTSEM problem. The proposed model is tested with a real high-speed railway line case in China. The simulation results of several cases with different system elements are presented, and the sensitivity analyses of several parameters are also performed. The obtained results reveal that it shows significant economic-saving potentials with the integration of HESS and renewable energy.

The Flexible Smart Traction Power Supply System and Its Hierarchical Energy Management Strategy

“…Inequality (19) represents that the power exchange between the microgrid and the 10kV distribution network cannot exceed the upper limit of its converter capacity. Inequality (20) denotes that the power output by the 10kV distribution network cannot exceed its own short-circuit capacity.…”

“…Lithium iron phosphate battery and UCs are used in ESS. The optimal configuration parameters of batteries and UCs can be obtained by the method in [20] which comprehensively considers their economic benefits to the traction power supply system. The method is as follows: (1) determining the daily investment cost when selecting a pair of PV and HESS capacity;(2) for each selected PV and HESS capacity, calculating the daily electricity cost before and after the installation of PV and HESS (the calculation method of daily power consumption depends on the specific system operation state).…”

“…An optimal economic operation optimization method that takes into account the short-term charge and discharge cost of ESS is proposed in [20]. However, the ESS model considered by this method is too complicated with high computation cost.…”

Regenerative Braking for Energy Recovering in Diesel-Electric Freight Trains: A Technical and Economic Evaluation

“…In [16], a methodology is proposed for optimal operation of railway electric energy systems considering renewable energy sources (solar panels and wind turbines), regenerative braking capabilities and hybrid electric energy storage devices (ultracapacitors and batteries). The authors of [17] presented an optimized sizing and scheduling of hybrid energy storage systems for high-speed railway traction substations integrated with removable energy, with the intention of minimizing the total cost throughout the project service period. The battery degradation and replacement cost were taken into account.…”

Control and Restrictions of a Hybrid Renewable Energy System Connected to the Grid: A Battery and Supercapacitor Storage Case

“…A fully active and semi-active topology for the battery and supercapacitor connections and their control is presented in [11,12], while a hybrid-diode based solution is described in [13]. This work relies on the most common parallel topology of the battery and supercapacitor connection, with a bidirectional DC-DC converter for each energy storage device, since this converter topology offers a better flexibility compared with other configurations and allows a full control action on each converter individually [14,15] with an implementation of a storage system filter in the control system of the ESS.…”