A Numerical Matrix-Based method in Harmonic Studies in Wind Power Plants

In the low frequency range, there are some couplings between the positiveand negative-sequence smallsignal impedances of the power converter due to the nonlinear and low bandwidth control loops such as the synchronization loop. In this paper, a new numerical method which also considers these couplings will be presented. The numerical data are advantageous to the parametric differential equations, because analysing the high order and complex transfer functions is very difficult, and finally one uses the numerical evaluation methods. This paper proposes a numerical matrix-based method, which is not only able to deal with those mentioned numerical data, but also it is able to consider all couplings between the positive and negative sequences. Keywords-Harmonic propagation; Harmonic stability; Resonance; Wind power plant; Wind Turbine Generator.