Doubly-fed Induction Generator Wind Farm Aggregated Model Based On IGKM Clustering Algorithm

With increasing number of wind farms and scale which leading to wind power generation in power system for a growing proportion.And also with the growing influence on the stability of power grid for power fluctuation.Wind power integration can be adversely affect for the power grid voltage,frequency,waveform and stability.As a result,the wind farm modeling is the basis of research on wind power integration.For accurately analyzing the dynamic characteristics of wind farm,with the thought of the coherency method,a method of wind turbine grouping based on improved genetic K-means(IGKM)algorithm is proposed.Specific works can be summarized as follow:(1)This paper briefly introduces the commonly used wind K means clustering algorithm and genetic algorithm basic principle and steps.By constructing an effective fitness function,and combining the advantages of the K-means clustering algorithm and genetic algorithm,a method of wind turbine grouping based on IGKM is proposed.Finally,writing the IGKM algorithm program on MALAB platform(2)Doubly-fed induction wind turbines mathematical model is set up.And the paper given Crowbar circuit resistance dereferencing methods.Through the simulation analysis of doubly-fed generator fault state of the rotor current and dc side voltage dynamic characteristics to verify the influence of triple factors which include the duration of the fault,voltage drop levels and fault time DFIG operating state on LVRT.Then the Crowbar commonly used two kinds of control strategies for simulation analysis and points out their respective advantages and disadvantages and applicable scope.And the Crowbar action area curve and Crowbar control strategy selection area curve been provided.The scope of application of the two control strategy to clearly identify.Finally,we get the Crowbar protection control strategy of Doubly-Fed Induction Generator.(3)The machine equivalent method of wind farm which including the measured wind speed and the Crowbar whether action as the fleet division index was came up.Falling income units machine terminal voltage by short circuit calculation,based on the wind speed data,determine the Crowbar the action of wind turbines.And then put the Crowbar action of wind turbines from the first moment of the "N" failure comes out independently in fleet and divided into a group,others what remaining units based on situation remains the same.Used the method of weighted capacity of each group of parameters,the wind farm is divided into a fleet of "N + 1".The model of machine equivalent method which considering both before failure moment all wind turbines running status differences and the effects of Crowbar circuit action can able to accurately reflect within the wind farm operation characteristics.(4)Through simulation analysis and comparison with the detailed model,single equivalent model,K-means the equivalent model and IGKM equivalent model for an actual wind farm.Results of the simulation show that IGKM clustering algorithm for fleet number k value has more flexibility and can Able to automatically identify differences in wind speed data values and has strong ability of searching the global optimal solution.According to the method established equivalent model of wind farms can accurately describe wind static and dynamic performance.At the same time in the transient process of considering the Crowbar movements on the impact of so as to improve the accuracy of equivalent model.