Research On Uncertainty Modeling Of Joint Power Of Multiple Wind Farms And Flexible And Efficient Wind Power Utilization Method Of The Grid

As the wind power construction continues to scale up and cluster in our country,the pressure on power consumption caused by the strong uncertainty characteristics of wind power generation has become increasingly severe,leading to escalating risks in the safe and economic operation of the power system.In this context,accurately quantifying the uncertainty of the joint power output of multiple wind farms and proposing optimal wind power consumption and operation strategies for the transmission-distribution systems has become an urgent problem.To address this issue,on the one hand,it is necessary to establish an accurate probability distribution model for wind power output,striving to reduce the model redundancy while ensuring reliability,so as to assist grid operators in reducing the conservatism of the operation plans.On the other hand,it is necessary to combine the diversified demands for efficiency and flexibility operation of the transmission-distribution systems,and propose appropriate scheduling strategies based on the existing policy mechanisms,so as to promote the coordinated cooperation and full utilization of wind power resources and flexible load resources.In light of this,the research is conducted from four aspects: uncertainty modeling of joint power of multiple wind farm,efficient consumption of wind power in the transmission system,flexible consumption of wind power in the distribution system,and coordinated consumption of wind power in the transmissiondistribution systems.The research can provide theoretical and technical support for the safe and economic operation of the power system under high-proportion wind power integration.The main contents are as follows:(1)For the problem of joint probability distribution modeling of high-dimensional wind power data,a modeling method based on the time-varying R-vine Copula theory is proposed.By fitting the temporal-spatial correlation of multi-wind power farms,the accuracy of the model is improved.First,the marginal distribution model for onedimensional wind power data is established based on the ARIMA-GARCH model,which fits the time series characteristics of wind power.Second,based on the Copula theory,the method of extending the one-dimensional marginal distribution model to a highdimensional joint probability distribution model is described.Then,the modeling process and calculation method of the time-varying R-vine Copula model are proposed,and on this basis,the joint probability distribution model of high-dimensional wind power data that considers temporal-spatial correlations is established.Simulation results show that the proposed model has good reliability,sharpness,and skill score performance.(2)For the problem of scenario forecast of wind power considering temporal-spatial correlations,a forecast scenario genration method based on the time-varying R-vine Copula theory is proposed.First,by combining the ARIMA-GARCH-t model and the time-varying mixed R-vine Copula model,the joint probability distribution model of the power of multiple wind farms is established.Second,based on the inverse computation process of the above two models,the sampling method of joint probability distribution model that alternately advances in the temporal and spatial dimensions is described.On this basis,the scenario forecast method for the power multiple wind farms is proposed.Simulation results show that the generated scenarios have similar fluctuation characteristics,temporal dimension autocorrelation characteristics,and spatial dimension cross-correlation characteristics to actual wind power.(3)For the efficient consumption problem of wind power in the transmission system,the robust constraints of wind power are established based on the Copula theory,and the robust consumption method for wind power in the transmission system is then proposed.First,the robust constraint set for wind power is established in three parts,including: the forecast error boundary constraints based on the kernel density estimation and the nonparametric 2-dimensional Copula model;the temporal dimension constraints based on the Mallet algorithm and the ARIMA model;and the spatial dimension constraint based on the non-parametric R-vine Copula model.Second,by combining the above constraints,the twostage robust optimization model of the transmission system is established.Finally,the solving process of the model is proposed based on the C&CG-PSO algorithm.Simulation results show that the proposed method can improve the economic efficiency of the system while ensuring the safe operation and wind power consumption of the grid.(4)For the flexible consumption problem of wind power in the distribution system,the operation strategy of the distribution system with the participation of multiple distributed wind power generators(DWPG)is proposed based on the typical transaction modes of distributed generation market.On the basis of combing the implementation framework of the three typical transaction modes,the decision models of multiple stakeholders is established,including:(a)for the DWPGs,the power reporting strategy based on the scenario method and the bidding strategy based on price-type DR are proposed;(b)for the users,the demand response model of flexible load under the guidance of market electricity price is proposed;(c)for the distribution system operator(DSO),by combining the source side and load side models,the optimization scheduling model under the market trading environment is proposed.Simulation results show that the proposed method is conducive to improving wind power consumption in the distribution system and supporting the realization of win-win benefits for the DWPGs,power users,and the DSO.(5)For the collaborative consumption problem of wind power in the transmissiondistribution system,a cooperative scheduling strategy is proposed based on the separation pricing mechanism of the transmission-distribution system and key wind power scenarios.Firstly,by combining the traditional peak load responsibility model and the electricity quantity responsibility model,the improved peak load-electricity quantity responsibility model is established while considering the impact of flexible load and wind power.Secondly,the multi-objective optimization framework for the transmission-distribution system was established by combining the aforementioned allocation responsibilities and the dispatching cost of the power grid.Next,based on five key wind power scenarios,a coordinated dispatching strategy for the flexible resources of the transmission-distribution system is derived,then,the coordinated multi-objective optimization scheduling model for the transmission-distribution system is further established.Simulation results show that the proposed strategy can promote the coordinated cooperation of flexible resources in the transmission-distribution system,thereby achieving a high level of centralized and distributed wind power consumption.