Economic Dispatch of Power System Considering Capacity Flexibility of Hydropower Reservoir

With the increase of load and the integration of renewable energy, the operation security region of power grid is decreasing. Therefore, the operation flexibility space of power grid should be fully exploited to expand the operation security region of power grid, so as to achieve the optimal allocation of resources. In this paper, a concept of capacity flexibility space of hydropower reservoir is proposed, and the operation flexibility model for capacity of reservoir considering the uncertainty of water inflow and risk cost is established. On this basis, an economic dispatch model is proposed to evaluate the operation benefit of power grid considering the capacity flexibility of reservoir. In addition, based on Karush-Kuhn-Tucker (KKT) conditions, the sensitivity relationship between capacity flexibility of reservoir and operation state variables of power grid is deduced, and a sensitivity identification method for critical capacity flexibility space of reservoir is proposed to utilize the critical capacity flexibility space of reservoir preferentially in power grid operation. Finally, the effectiveness of the proposed method is verified on IEEE 30-bus system and an actual regional power grid. The simulation results dedicate that, on the basis of considering the demand of flood risk control of a reservoir, the proposed method can effectively utilize the capacity flexibility space of reservoir to adjust the reservoir water storage flexibly, promote the hydropower and wind power consumption, as well as reduce the operation cost of power grid. © 2020 Automation of Electric Power Systems Press.