Hierarchical dispatching method based on Hungarian algorithm for reducing the battery degradation cost of EVs participating in frequency regulation

: Electric vehicles (EVs) as the frequency regulation (FR) resources with fast response speed provide a promising solution to improve FR performance. However, the exorbitant battery degradation cost (BDC) restricts EVs providing FR service. To achieve the FR performance with cost-efficiency, a hierarchical dispatching method based on the Hungarian algorithm is proposed for reducing the BDC of EVs in this study. To ensure system security, the required FR power is dispatched to FR units and EV aggregators according to the optimization coordinating strategy for reducing frequency fluctuation. Then, EV aggregators further dispatch the power to each EV for reducing the total BDC of EVs. In the dispatching process, various EVs provide FR service in the light of their actual condition such as BDC characteristics and state-of-charges (SOCs). To calculate the BDC of EVs accurately, the corresponding cost formulas that consider various EVs are fitting for guiding power dispatching. According to the sensitivity analysis, the FR regularity of EVs about FR performance is drawn for promoting the quantity of EVs participating in FR and further improving FR performance. Extensive case studies are presented to validate the effectiveness of the proposed method, where a large number of EVs participate in FR with cost-efficiency.