Research On Voltage Stability Coordination Control Method For Distribution Network With Distributed Wind Power

In order to adapt to high penetration,large-scale distributed power sources,and improve the high degree of compatibility of distributed renewable energy generation,Active Distribution Network(ADN)emerged.The ADN requires to make full use of the distribution generation's own characteristics to make it actively participate in the regulation and control of the power grid.With the development of wind power technology,currently more wind farms are connected to the grid by power electronic converters.With these converters,the reactive power regulation capability of the distributed wind power greatly improves,and thus they have better voltage regulation performance.In order to realize distribution generations voltage control coordination in regional power grid,this paper proposes a voltage stability coordination control method for distribution networks with distributed wind power.Firstly,the different methods of voltage stability analysis are introduced.The sensitivity method and continuous power flow method for analyzing static voltage stability are discussed in detail and their application characteristics and application direction are also discussed.The operation principle of the automatic voltage control(AVC)system in current domestic power system is analyzed in detail,and the method of Ground-to-Wind two-level coordination control system structure is put forward as the system operation basis to realize the method proposed in this paper.Secondly,the grid-connected reactive power characteristics of the variable speed constant frequency(VSCF)wind turbine are analyzed emphatically,and the calculation method of the reactive power limit of the wind turbine is deduced.The reactive power calculation methods of reactive power compensation devices and reactive power consumption equipment in wind farms are also analyzed.In order to ensure the stability of wind farms its own when they participate in regional voltage regulation,a calculation method for dynamic reactive reserve capacity of wind farms is proposed.Based on these calculation,a method for calculating the reactive power output characteristics of a wind farm that is suitable for wind farms to participate in regional voltage regulation is proposed.Then,a distribution generations voltage control adaptive zone-division method based on cluster analysis is proposed.Distributed located distribution generations in the syetem are coordinated in the regional AVC.The reactive-voltage sensitivity is used to distinguish the distribution generations control ability to each node of the distribution network,and thus to establish the reactive power control space.The cluster analysis is used to dig out strong control area for the distribution generations,by this way,the voltage regulation efficiency of distribution generations can be improved.Finally,on the DIgSILENT/Power Factory simulation platform,a city power grid with multiple distributed wind power is built.The comprehensive simulation analysis of the proposed method is performed on this platform to verify the effectiveness of the proposed methods.