Research On The Optimization Of The Power Grid Operation Considering Wind Variability And Uncertainty

Because of the fossil energy crisis and environmental problems,renewable energy has got a lot of attention.Especially with the proposal of "3060" carbon emission target,developing renewable energy has become an important measure to promote China’s energy transformation and sustainable development.The renewable energy sources such as wind power develops rapidly and has the largest scale,but its output is variable and uncertain.The traditional power grid mainly relies on the flexible regulation capacity of the generation side to cope with the fluctuations of wind power and maintain the balance of power supply and demand.But with the large-scale wind power integration,the fluctuation and uncertain factors increase,and the system regulation pressure increases,which poses new challenges to the safety and economics of power system operation.These include: the definition of wind variability and uncertainty,the quantitative analysis of wind variability,the optimization of power system scheduling strategy including wind power,and wind power producer bidding strategies.Under this background,from the viewpoint of wind power variability,this paper researches on the quantitative analysis of wind variability cost and the optimization method of reducing variability cost.From the viewpoint of wind uncertainty,this paper researches on the economic dispatch method of power system and offering strategies of the wind power producer.The main work of this paper is as follows:In view of the problem that the wind power variability is difficult to calculate,an analysis method of wind power variability cost is proposed.Firstly,based on the characteristics of wind power,the volatility and uncertainty are clearly defined,and the components and influencing factors of wind power variability cost are studied.To analyze the ramping cost caused by thermal power units,the calculation method is given based on the Manson coffin model.On this basis,an alternative scenario construction method is proposed to calculate the variability cost from the viewpoint of the power system schedule.Considering the smoothing effect of multiple wind farms,this paper proposes the calculation method of variability cost of wind power cluster.Furthermore,based on the cooperative game theory,the smoothing benefit allocation strategy of multi wind farms is studied.The simulation results show that the proposed method can effectively analyze the additional costs caused by wind power fluctuations,and provide guidance for system operators to mine the value of wind power and make decisions.To solve the problem of wind power variability,a coordinated optimization strategy of supply and demand side resources is proposed.Firstly,the characteristics of energy storage and demand response(DR)resources are studied,and the advantages and disadvantages of these two kinds of resources in reducing wind power fluctuations are analyzed.Considering the individual differences of users,the demand response model based on the dynamic elasticity coefficient is constructed,and the demand response strategies based on the price-based DR program and incentive-based DR program are studied.On this basic,an optimization approach considering demand response and energy storage is proposed and the effectiveness of different resources to reduce the fluctuation of wind power is analyzed.Simulation results show that the proposed coordinated scheduling strategy can effectively reduce the variability cost of wind power and improve the flexibility of system operation.In view of the problem that the uncertain process of wind power and demand response is difficult to be represented by accurate probability density distribution,an economic dispatch method based on the information gap decision theory(IGDT)is deployed.The IGDT model is an inexact probabilistic uncertain optimization method,which does not need to assume the distribution of wind power output and demand response capacity in advance.To solve the economic dispatch problem of wind power system,a two-stage optimal dispatch strategy is proposed: in the first stage,the unit commitment optimization method of wind power system is studied without considering uncertainty;In the second stage,considering the uncertainty of wind power and demand response,an economic dispatch strategy based on the IGDT method is proposed.The robust IGDT model and the opportunistic IGDT model are constructed respectively,and the impact of uncertainty on the dispatch strategy is studied.The experimental results imply that the inexact probabilistic uncertain optimization method provides a new solution to the economic dispatch problem considering uncertainty.The proposed method can effectively manage the risk caused by the uncertainty of wind power and demand response,and reduce the operation cost of the system.To reduce the revenue risk caused by the prediction errors,an optimal offering strategy for wind power producer is proposed.Firstly,to maximize the day ahead revenue of wind power producer,a demand response trading mechanism between wind power producers and different types of users is designed;Then,considering the uncertainty faced by wind power producers,a decision-making model based on the IGDT method is constructed;According to the risk attitudes of of wind power producers,a robust model and an opportunity model are constructed to optimize the bidding strategies of risk averse and risk seeking decision makers;Furthermore,considering the uncertainties of wind power output and demand response,a dual objective decision optimization model is established,which is solved by the normal boundary intersection(NBI)method and fuzzy theory.The simulation results show that the proposed method can effectively help wind power producers to build appropriate bidding strategies and reduce the deviation penalty caused by uncertainties.