A day-ahead bidding strategy for battery swapping and charging system participating in the regulation market

The battery swapping mode is a promising way for electric vehicles (EVs) to participate in power grid frequency regulation. However, the operation mechanism and the uncertainty management in the process still lack research. Aiming at this issue, this paper proposes a day-ahead bidding strategy for the battery swapping and charging system (BSCS) providing regulation reserve capacity in the ancillary service market. Firstly, a new BSCS-based regulation model is established. Then, an ambiguity set based on Kullback-Leibler (KL) divergence is used to manage the uncertainty of regulation signals and battery swapping demands. Furthermore, a boundary expectation approach is proposed to turn the problem into robust optimization. Finally, after using the extreme scenario method (ESM) to generate extreme scenarios, a duality-free column-and-constraint generation (C&CG) algorithm is employed to solve the problem. The case studies demonstrate that BSCS can provide economical and robust reserve capacity bidding plans in the day-ahead market with the proposed strategy. At the same time, the BSCS-based regulation service is simulated with the battery development trend in the future, and suggestions are given.