Managing Uncertainties in Wind Farm Harmonic Studies Using Unscented Transform

Uncertainties in power system studies are often considered using Monte Carlo methods, or by the use of deterministic methods, often based on some worst-case assumptions. With an increasing number of uncertainties, there is a need for methods that can estimate statistical parameters from a limited number of calculations. This paper utilizes a method called the Unscented Transform together with Cornish-Fisher expansion to calculate harmonic distortion at the point of connection of a wind farm under different uncertainties. The method is shown to be able to estimate the 95% value of individual harmonics accurately when considering variations in emission and impedance, using only a limited number of calculations.