A method to model the output power of wind farms in composite system reliability assessment

This paper introduces a method to estimate the output power of a wind farm for composite reliability evaluation. The proposed method is presented in terms of capacity outage probability and frequency table (COPAFT) considering the mechanical failure of wind turbine generators (WTG) and the correlation between the outputs of turbines on a wind farm. Based on the proposed method, the output power of a wind farm is modeled as a single source with multiple derated states. The method has been applied on the IEEE RTS to investigate the effect of considering the mechanical failures of wind turbines on system reliability indices. The wind power is allocated at different buses of the IEEE RTS to calculate the well known reliability indices. The obtained results confirmed that locating wind farms at the buses that at a high risk enhances the overall reliability of the system than placing these farms at the buses of low risk. The proposed method provides a straightforward steps to estimate the outage of wind power due to input availability and mechanical failure of WTG. Further, it reduces the complexity of modeling the output power of wind farms considering the stochastic nature of wind speed and WTG mechanical availability.