Medium-and long-term wind farm output scenarios are usually required for power system planning. However, with the traditional medium-and long-term wind power output time series generation method, it is difficult to simultaneously take into account the spatiotemporal correlation of multiple wind farms, leading to the failure of the output sequence to reflect their medium-and long-term statistical characteristics. Hidden Markov model (HMM) can simultaneously consider the temporal and spatial correlation of multiple wind farms, but the existing HMM method is not accurate in describing the output distribution of multiple wind farms, which leads to a large error between the model output and the actual wind power output. Therefore, this paper proposes a method for generating medium-and long-term correlated output time series of multiple wind farms based on the Gaussians mixture Hidden Markov model (GMM-HMM). The discrete state variable in the hidden Markov model is used to describe the meteorological state. The Markov chain between discrete state variables is used to describe the temporal correlation of wind power output. The wind power output vector of multiple wind farms is used as the observation variable, and the mixed Gaussian probability distribution mapping relationship between the state variable and the multidimensional wind power output vector is established. Based on the Monte Carlo sampling method, the multi-wind farm output series satisfying the spatiotemporal correlation of historical output series are generated monthly. In the calculation example, the monthly wind power output series generated by five wind farms in Jilin Province are analyzed. The results show that the main statistical characteristics of the multi-wind power output time series generated by the proposed method are generally superior to those obtained with the traditional wind power output modeling method, which proves the superiority of the proposed method.
INDEX TERMSMultiple wind farms, spatiotemporal correlation, Gaussians mixture Hidden Markov model (GMM-HMM), time series generation NOMENCLATURE Most of the symbols and notations used throughout this paper are defined below for quick reference.