Research On Multi-position Coordinated Optimized Control Technologies Of The Dispersed Wind Power Grid-Connection

With the implementation of relevant policies,dispersed wind farms(DWFs)have become one of the most important way to consume the renewable energy.The coordinated optimization and control for distributed wind connect to grid have become a hot research topic.While the existing works mainly consider the single-point access scenario,and does not fully consider the coordinated control of multi-point access for the wind farm level.Without fully analyzing the features of power factors and dynamic response,and also lack of the combination analysis of DWF power consumption and load volatility,grid’s peak-to-valley difference,etc.For the purpose of stability,economy and energy consumption,this paper constructs a two-layer cooperative control method for multi-point access in distribution network,and gives the control strategy based on the variable power factor and reactive dynamic response,and proposes the coordinated optimization strategy based on the adjustable load.The main research contents are as follows:1)Introduced the modeling and control of distributed wind turbines and compared with 3 types of wind turbines.Considering the wind turbines’ structures,operation characteristics and control methods,the adaptability of doubly-fed wind turbines connect to the distribution network and the influence of reactive power and voltage are explored.To verify the effectiveness of the control strategy,the simulation model of the distributed wind turbine is built.The achievements can provide the foundations of analyzing the operation and control for grid-connection.2)Proposed a double-layer distributed wind power multi-point coordinated control strategy.The research results show that the multi-point coordinated control strategy based on minimum network loss and voltage deviations can effectively reduce the network loss and increase the bus voltage level of the distribution network,increase the load capacity of the distribution network,and increase the stability of the system,the whole system can achieve coordinated and optimized operation.3)Proposed a dynamic power factor optimization strategy.For the reactive power requirements of wind power connected to the grid,through analyzing the load features,a general load model based on voltage static characteristics is established.Then based on the analysis of dynamic power factor and reactive power dynamic characteristics,a multi-objective function based on network loss,voltage deviation and power supply reliability are developed.By solving the multi-objective function,the optimal dynamic power factors of DWFs’ operation and control can be obtained.In addition,to solve the developed function,an improved firefly algorithm(IFA)by chaos theory is introduced.Compared with the existing optimization algorithms.The calculation results of IFA show that the proposed dynamic power factor can effectively reduce the network loss and node voltage deviation under different load types,and the operational stability and economy of the distribution network are improved.4)Proposed dispersed wind power and variable load coordinated optimization strategy.In terms of local consumption and coordinated optimization,firstly,the coordinated operation characteristics of the source network load are described.Secondly,the flexible resources are modeled,based on the comprehensive consideration of electric vehicles(EVs),loads,reactive power compensators and electricity prices,for the purpose of developing the wind power maximum consumption,the overall optimal economic performance,peak-to-valley difference and the voltage deviation,a multi-objective optimization function is constructed.To combine the different indicators,the entropy weight method is introduced by considering source side,grid side and load side.At lastly,the multi-objective optimization function is solved by the proposed IFA and used to verify the effectiveness of the proposed control strategy.Additionally,compared with the results of non-optimized scheduling and single optimization scheduling,the superiority and effectiveness of the proposed comprehensive control strategy are proved.The roles of DWF can change from passive performers to active participants in distribution networks.