A Practical Short-Circuit Current Calculation Method for DFIG-Based Wind Farm Considering Voltage Distribution

Abstract

This paper presents a calculation method of short-circuit current (SCC) for doubly fed induction generator (DFIG)-based wind farm considering the voltage distribution characteristics. When a short-circuit fault occurs in a wind farm, a large SCC will be contributed by the dozens or even hundreds of DFIGs in the wind farm. And the security and stability of the wind farm will be affected by the SCC. The SCC characteristics of the DFIG are closely related to its post-fault terminal voltage (PFTV). Therefore, a practical calculation model of SCC in single DFIG is proposed in this paper, based on the electromagnetic transient analysis. And according to a correction method of the topological matrix for a post-fault wind farm proposed in this paper, the relationship model between voltages and currents under short-circuit faults is established. Then, the PFTVs and SCCs of the DFIGs in the wind farm can be obtained by solving the model equation. Finally, the proposed method is validated through MATLAB/Simulink-based simulation results, and a comparison with the national standard calculation method is analyzed. The results show that this method has better accuracy, which provides a more accurate basis for the electrical safety design of wind farms.