Distributionally robust dispatch of power system with advanced adiabatic compressed air energy storage for frequency security

In response to climate change and the need to decrease carbon emissions, the penetration of renewable energies into power grids is growing dramatically. Meanwhile, intermittence and low inertia of renewable energy pose significant risks to frequency security. The advanced adiabatic compressed air energy storage (AA-CAES) is a promising solution to enhancing grid frequency security due to its flexible and high inertia properties. Therefore, based on distributionally robust optimization, this paper proposes a dispatch strategy with the participation of AA-CAES to enhance frequency security. Firstly, a dispatch-friendly model of AA-CAES is proposed and can reflect the effect of the part-load features on the dis-/charging efficiencies and capacities. Subsequently, a frequency response model with AA-CAES is presented to establish frequency security constraints, ensuring compliance with minimum inertia and maximum frequency deviation requirements. Furthermore, to address the randomness of renewable energy, this proposed model is formulated as a two-stage distributionally robust optimization problem. In the day-ahead stage, the optimal on/off schedules for generators and AA-CAES are determined to provide sufficient grid inertia according to the worst probability distribution. In the intra-day stage, the generation and AA-CAES are adjusted to minimize the frequency deviation. Finally, numerical studies demonstrate the validity of the proposed strategy in supporting frequency security. The results show that when AA-CAES adopts constant-pressure-hybrid-control mode on the compression side and constant-pressure-throttling-control mode on the expansion side, the expectation value of frequency deviation is 0.018 Hz, and the frequency security improvement is the best among modes. By adjusting the confidence level and the quantity of sampling data, operators can improve the dispatch economy. When the renewable integration rate reaches 50 %, the proposed strategy can maintain the frequency within the required range and adapt to the high renewable integration.