Research on identifying parameter of DFIG-based wind farm based on mathematical mechanization analysis

Abstract

In order to obtain precise running parameters which are the intrinsic cause resulting in sub-synchronous resonance (SSR) in transmission line with series compensation capacitor, an approach that can be used to identify the dynamic equivalent parameters of DFIG (doubly-fed induction generator) -based wind farm has been proposed based on the mechanized mathematics theory. Core work is to derive the analytical expressions of the stator resistance, inductance and the rotor resistance, inductance and the mutual inductance which are expressed by the sampling voltage, current and active power based on polynomial modelling and characteristic set of the mathematical mechanization. Simulation results which are associates with the actual sampled data of a wind farm show that, the equivalent parameters consist of 32 DFIGs have been given and verified by proposed approach. Also, the maximum identifying error of corresponding resistance and inductance of the stator and rotor was lower than 5% based on sampling an actual DFIG farm. This work can provide a reference for analysing and suppressing SSR which is a bottleneck for a wind farm stable running.