Johnson system for short-term wind power forecast error modeling

Despite the large number of wind power forecast methods being proposed, forecasting errors are inevitable; thus, an accurate description of wind power forecast error (WPFE) is vital and is the focus of this paper. On a short-term forecasting scale, the distribution shape of the WPFE exhibits asymmetric and leptokurtic characteristics; however, common existing WPFE distribution models, such as the normal distribution, Laplace distribution and beta distribution, cannot fully describe the WPFE. This paper proposed the Johnson system to describe the WPFE, as this system has flexible skewness and kurtosis ranges and easy to implement. Based on actual WPFE data, the performance of the Johnson system is compared with those of the common distribution models proposed in the literature, and the results show that the Johnson system can represent the WPFE of all output levels of wind power and forecasting scale well.