1.Department of Electrical Engineering, Tsinghua University, Beijing 100084, China;2.North China Branch of State Grid Corporation of China, Beijing 100053, China

As an important new type of flexible load resource, electric vehicles (EVs) have the potential to provide regulatory services for the power grid. However, the controllability of EVs is affected by their traveling arrangements, which shows the regularity and uncertainty. Firstly, this paper proposes a flexibility model of EVs, which can consider the difference in the data structure of public charging piles and specific charging piles. Besides, the uncertainty of the flexibility is described using the data-driven distributionally robust chance constraint (DRCC). Furthermore, considering a charging operator aggregating different types of charging stations participating in the peak regulation ancillary service market, the paper proposes a bi-layer bidding and allocating model, which enables the charging operator to manage the risk outside and to flexibly dispatch resources inside. Simulation results based on the actual data indicate that the flexibility described by the DRCC can adapt to the random changes of traveling law of EVs, and the proposed bidding and allocating strategy can effectively manage the revenue of the charging operator and the default risk.