The Study On The Influence Of Reactive Compensation For Voltage Stability Of Wind Farm Incorporated System

With the rising of public awareness for environment protection, the wind energy, asa clean and renewable energy, is attached great importance by countries all over theworld, and wind power generation has become an important development direction ofmany countries’ energy strategy. The impact of wind power on power grid isbecoming more and more serious as increasing of the proportion of the scale of windpower in the grid. Among them, the problem of the voltage stability on wind powersystems is one of the most serious problems in wind farm incorporated system, thedirect and effective method for solving the problem of voltage stability is reactivepower compensation. STATCOM (Static Synchronous Compensator) is representativeof the latest technology in the field of reactive power compensation. It is has the meritof fast response rate, good stability, and continuous output of reactive power, so issuitable for reactive power compensation to improve voltage stability of the system.This paper firstly analysis the calculation model and the working principle of theDoubly-Fed Induction Generator wind turbine, including the speed model, windturbine, generator and converter structure, the dynamic model of DFIG is establishedin the d-q synchronous rotation coordinates of each part. Select Static SynchronousCompensator STATCOM as the dynamic reactive power compensation device, isestablished in the d-q synchronous rotation coordinates. On this basis, the operatingprinciple of reactive compensation is introduced when the grid voltage sags or swells;the feed-forward decoupling control strategy of stator voltage oriented is analyzed.Then this paper takes wind farm as an example which is connected to IEEE-9bus system. In order to considerably improve the static voltage stability, strategy foroptimal location of STATCOM, identifying the reactive compensation point andreactive power compensation of STATCOM in the system by the method proposed inthis paper which is based on reactive power margin. For sensitivity index value of the system as reason, testified the effectiveness and correctness of the proposed methodin this paper. Do the simulation after compensating the system，the results show thatSTATCOM has a great influence on improving voltage stability of wind power gridsystem..