1.China Electric Power Research Institute (Nanjing), Nanjing 210003, China;2.State Grid Zhejiang Electric Power Co., Ltd., Hangzhou 310063, China

In the scenario of high proportion of renewable energy access, how to improve the flexibility of the power system has become a focus. Electrochemical energy storage can improve the flexible regulation ability of new power systems, but its technical characteristics are different from conventional market players, so it is necessary to design the corresponding market participation mechanism. Therefore, according to the relationship between depths of charge and discharge, charging and discharging ratio of energy storage and aging cost, a price difference bidding mode suitable for energy storage participation is proposed. In this bidding mode, the energy storage can declare the cost under different operation states and different depths of discharge, so as to release the deep charging and discharging capacity of the energy storage. Considering the coupling relationship between energy storage frequency regulation capacity and state of charge, the market clearing model is established for the coupling of day-ahead energy market and frequency regulation market. The case results show that the proposed mechanism can fully reflect the market value of energy storage, promote the optimal allocation of energy storage resources, and improve the market revenue of energy storage.