Research On Economic Dispatching Of Wind-storage Combined System Considering Peak-shaving Demand

Due to the strong randomness,volatility and anti-peak regulation,wind power output can’t meet the peak regulation requirements of the power system during peak or trough load periods,making power system dispatch more difficult.But the energy storage system can effectively alleviate the peak shaving pressure of the power system.Considering the advantages and disadvantages of the dispatchability of wind-storage combined system,the influence of the factor on the formulation of system dispatching plans is less researched.Therefore,this paper takes the economic dispatch of the power system with wind-storage system as the main body,and takes the dispatchable capacity of the wind-storage combined system as the points of focus to research.And the peak regulation capacity of the wind-storage combined system is fully mobilized While ensuring the safe and economical operation of the power system.The specific research contents and conclusions are as follows:(1)This paper studies the construction method of power system optimal dispatch model considering wind power forecast errors and the influence of system dispatch by the inherent characteristics of wind power output.Under the theory of chance-constrained programming,random variable constraints are used to model wind power forecast errors,so as to construct a basic model of power system optimal dispatch considering wind power forecast errors.(2)This paper proposes an evaluation system and comprehensive evaluation method that considers the peak regulation capacity of the wind-storage combined system.In order to quantify the advantages and disadvantages of the dispatchable capacity of the wind-storage combined system,this paper proposes an evaluation indicator system for the peak regulation capacity of the wind-storage combined system,which includes indicators such as wind power output prediction accuracy,output volatility,and energy storage health status;Using the entropy method to empower objectively to various indicators in the evaluation system,and quantify scientifically the peak regulation capacity indicators of the wind-storage combined system;Analyzing the effectiveness of the evaluation indicators from two aspects of system backup configuration and dispatch power allocation,lays a theoretical foundation for the construction of the economic dispatch model of a wind-storage combined system that takes into account the peak regulation requirements.(3)This paper constructs an economic dispatch model of the wind-storage combined system that takes into account the peak regulation requirements,and the indicators of the peak regulation capacity of the wind-storage combined system is introduced into the power system dispatch model with wind power grid-connected.The model takes the system operating cost and the deviation of wind power utilization rate as the comprehensive objective,takes rolling scheduling as the time scale,and takes power balance,unit climbing,energy storage charging and discharging power as constraints to solve the optimal dispatch plan of the system.(4)Based on MATLAB and YALMIP toolbox,performing simulation verification on the economic dispatch model of the wind-storage system constructed in this paper.At first,performing simulation verification on the evaluation indicator system of the peak regulation capacity of the wind-storage combined system.Then,applying the economic dispatch strategy of the wind-storage combined system that takes into account the peak regulation requirements to the IEEE 39 nodal system.And verifying that the model in this paper can take account of dispatch economy at the same time ensuring the safe and reliable operation of the system from the aspects of wind-storage system dispatch plan and operating cost.Finally,this paper uses the North Jiangsu Power Grid as an example to verify the feasibility of the dispatch strategy.