Study On Short-Term Optimal Scheduling Of Cascaded Hydropower Plants In Electricity Market Environment

With the reform of China’s electricity market and the step-by-step development of the river basin cascade hydropower plants,the upstream and downstream hydropower plants have started to actively participate in the electricity market jointly.In order to further improve the formulation accuracy of short-term optimal dispatching plan of cascade hydropower plants and enhance the benefits of cascade hydropower plants participating in the electricity market,this paper analyzes the influence of dynamic water flow delay between cascade hydropower plants on short-term optimal dispatching plan,and further optimizes the problem of continuous flow distribution in two time periods in the model to help reduce dispatch deviations.A short-term optimal dispatching model for the participation of cascade hydropower plants in the portfolio electricity market and a joint optimal dispatching benefit compensation model for hydropower plants with different affiliated interest subjects are established which effectively improve the generation revenue of cascade hydropower plants and promote the cooperative operation of hydropower plants with different affiliated interest subjects upstream and downstream.The main research contents of this paper are as follows.(1)Establishing a model for maximizing the power generation of a cascade hydropower plants with coupled dynamic water flow delay.Taking the maximum power generation of the cascade hydropower plants as the optimization criterion,the model further optimizes the continuous distribution of flow in two time periods,analyzes the influence of dynamic water flow delay on the short-term optimal scheduling results,and compares with the constant delay scheduling model and the ignored delay scheduling model.The results show that the real dynamic water flow delay optimization model established in this paper can improve the power generation of cascade hydropower plants by 0.64% compared with the constant delay scheduling model,and reduce the scheduling deviation compared with the ignored delay scheduling model.The water flow delay between cascade power stations has a greater impact on the process of water level change in individual hydropower plants and the process of power output in time periods.(2)A short-term optimal dispatching model for participation in the portfolio electricity market by the cascade hydropower plants is established.Taking the maximization of power generation revenue of the cascade hydropower plants participating in the portfolio electricity market as the optimization criterion,the influence of the contract electricity coefficient on the optimized dispatching results and the difference between the dispatching results of the model of participating in the portfolio electricity market and the model of maximizing power generation are analyzed.The results show that the established model can real-time follow the day-ahead market clearing price and effectively improve the revenue of participating in the electricity market for the cascade hydropower plants.As the contract electricity coefficient increases,the power generation of the cascade hydropower plants improves and the power generation revenue decreases.(3)The proposed method of joint optimal dispatching benefits compensation for hydropower plants with different affiliated interests.The idea of deviation square and Shapley value are combined to compensate the benefit between hydropower plants.The proposed method takes into account other factors of hydropower plants that cannot be directly translated into power generation benefits,which effectively compensates for the shortcomings of the single Shapley value method and makes the developed benefit compensation scheme more acceptable to the members of the alliance.