Research On Harmonic Data Analysis And Harmonic Model In Wind Farm

As a specific harmonic source, Doubled- Fed wind turbines had a serious impact on the grid. Mainly focusing on the practical problems of wind farm in recent years, this paper had research on the relation between the doubled-fed wind turbine and the grid. Through the measured data and simulation, the internal co-relationships were found out and analyzed with MATLAB.The major contributions of this thesis work are listed as following:(1)Based on the measured data and the simulation waveform analysis, we can acquire the occurrence regularity of harmonic, inter-harmonic and high frequency harmonic of doubled fed wind turbine, and discuss harmonic under the unbalance condition of the grid voltage. Combining with all the analysis, the unified harmonic model of doubled-fed wind turbine is established, obtained, and proved its validity and accuracy through measured data.(2) Based on the method of designing the fourth edition of IEC61400-21, this paper discussed and analyzed the harmonic phase of each unit in wind farm, and acquired the assessment method of harmonic superposition in wind farm. Simulation results show the method is validity and effectiveness. Through the repeated experiments, the new principle is proposed and discussed. Taking examples is to verify its importance.(3)The superposition of harmonic in wind farm was predicted and evaluated with Monte-Carlo method in this paper. Large volumes of voltage and current data in wind farm was measured and analyzed for exploring the distribution rules of harmonic current amplitude and phase, based on which, the probabilistic statistical model of harmonic current in wind farm was set up. And the superposition of harmonic in wind farm was predictedand evaluated with Monte-Carlo method. This method can be used to calculate the mean value of the superposition of harmonic and predict the harmonic aggregation at extreme situations. Simulation shows that the calculation of harmonic superposition with Monte-Carlo method has strong reliability and maneuverability.