A Robust Optimization Model for Electric Vehicle Aggregator Participation in Energy and Frequency Regulation Markets Considering Multiple Uncertainties

In order to fully exploit the market value of electric vehicle (EV) participation in the electricity market, EV aggregator (EVA) can aggregate large number of EV resources to participate in the day-ahead energy and frequency regulation markets as a bidding entity. To address the problem that EVA face multiple uncertainties in bidding decisions to participate in the electricity market, a response capability evaluation model of EVA is developed, the uncertainty characteristics of EV users' willingness to respond, frequency regulation signals and market electricity prices are modeled, and a robust optimization model for EVA participation in the energy and frequency regulation markets considering multiple uncertainties is constructed. Firstly, the energy and power boundaries of an individual EV are evaluated, and the energy and power boundaries of the EVA are obtained by aggregation, based on which the response capability evaluation model of the EVA is constructed. Furthermore, the uncertainties facing by EVA participation in the energy and frequency regulation markets are modeled. Among them, EV users' willingness to respond is characterized based on consumer psychology principles, and EVA energy accumulation triggered by frequency regulation signals is portrayed by frequency regulation energy coefficients. Uncertainties including EV users' willingness to respond, frequency regulation signals and market electricity prices can be handled by robust optimization methods. Finally, A robust optimization model for EVA participation in the energy and frequency regulation markets considering multiple uncertainties is constructed with the objective of maximizing the net bidding revenue of EVA. The bidding strategies of EVA in the day-ahead electricity market under several scenarios are constructed and their net bidding revenues are compared. The case simulation results show that the proposed robust optimization model can reasonably formulate the dispatching strategy for EVA to participate in the day-ahead energy and frequency regulation markets. Based on the case simulation results, the main conclusions can be obtained as follows. ① EVA mainly profits by participating in the frequency regulation market, and it is more appropriate for EVA to participate in the frequency regulation market in order to fully reflect the market value of EVA. ② Increasing the incentive level can increase the response willingness of EV users, which in turn increases the response capability of EVA, and to a certain extent can improve the bidding revenue of EVA. However, increasing the incentive level may make the dispatching cost of EVs increase significantly, and the net revenue of EVA decreases instead. Therefore, EVA should set a reasonable incentive level according to the frequency regulation demand. ③ Increasing the robust control coefficient can reduce the bidding risk of EVA, but the net bidding revenue also decreases. The robustness of different uncertainty factors has different degrees of importance on the net bidding revenue of EVA, among which the uncertainty of frequency regulation signal has the greatest impact on the net bidding revenue of EVA. ④ The model proposed comprehensively considers the impact of various uncertainties faced by EVA in the energy and frequency regulation markets joint optimization bidding decision, and the optimization results can provide a reliable reference for EVA's bidding decision. © 2023 Chinese Machine Press. All rights reserved.