Point Estimation Method Considering Estimator Boundary Constraints to Calculate Probabilistic Power Flow

Point estimation method is commonly used to calculate probabilistic power flow due to its accuracy and efficiency. However, it may cause relatively large errors when dealing with some probabilistic models, such as wind farms which have cut-in and cut-out constraints. This paper proposes the idea of equal constraint transformation and power transformation to solve this problem. First, the mathematical model of electricity system is constructed. Second, the idea of power transformation is utilized to transform wind speed from asymmetry into symmetry to ensure that the estimated point locates within the limit. Third, equal constraint transformation method is used to estimate the power generated by wind farms. Finally, time-domain simulations are performed to verify the effectiveness of the proposed two methods.