Measurement based parameters estimation of large scale wind farm dynamic equivalent model

For the past few decades, the drastic increase in the installed capacity of wind farms (WFs) has necessitated a computationally efficient dynamic equivalent model of a WF, which can be used for accurate power network simulations. Various doubly-fed induction generators (DFIGs) with sophisticated power control, rotor, and grid side converter control based models for wind turbine (WT) exist in the literature. However, these models are computationally burdensome and restrict their application for modeling large WFs. Thus, an equivalent DFIG based model of a WF, with the rotor circuit modeled as a constant current source, is proposed in this paper. The proposed model is simple and computationally efficient as no rotor measurements are required, and voltage and current measurements at the point of common coupling (PCC) of the WF are used in extended Kalman filter (EKF) to evaluate the dynamic parameters of the equivalent DFIG. A Y-bus based reduction is also proposed for the equivalent collector system's impedance. Simulation results on a test WF in MATLAB Simulink and DIgSILENT prove the proposed model's efficacy over the existing equivalent models for different operating conditions like wake effect and contingencies in the interconnected power system network. (c) 2020 Elsevier Ltd. All rights reserved.