Study on Low Frequency Oscillation of Wind Power System Based on HHT
For the output of wind power system has the characteristics of randomness, volatility and intermittence, the voltage of wind power system low frequency oscillation is one of the most common fluctuations in the system. For the problem of low frequency oscillation, the limitations of the detection methods such as the Lyapunov linearization method, the Prony method, wavelet transform method are summed up, and a new detecting method named Hilbert-huang Transform (HHT) is put forward in this paper, which can detect the oscillation accurately and timely. To solve the problem of end effect in the process of empirical mode decomposition (EMD), B-spline empirical mode decomposition based on support vector machine is applied in dealing with the end issue. an extension of the original signal is applied. Then, calculating the average curve of the signal by B-spline interpolation method. Finally getting the intrinsic mode function (IMF) by empirical mode decomposition (EMD). The practicality of the method is verified by Matlab simulation.