Research on short-circuit current of doubly fed induction generator under non-deep voltage drop

• We present the equivalent models of DFIG for short circuit current calculation of power system.
• We deduce the complete expressions of the short-circuit current contributed by DFIG.
• The features of short-circuit current of DFIG under partial voltage drop are proposed.
• Both the generator transient and exciting regulation of DFIG are taken into account.
• We construct a succinct vector model of DFIG for transient analysis.

The transient characteristics of power systems with large-scale doubly fed wind turbines undergo profound changes. Doubly fed induction generators (DFIG) under non-deep voltage drop generate short-circuit currents, which involves complicated electromagnetism and control coupling. This phenomenon has only been partially studied in the literature. Thus, this paper presents a detailed analysis of the short-circuit current of DFIG, with particular attention to the influence of converter adjustment. The dynamics of generator and converter control were simultaneously analyzed by vector analysis in uniform coordinate space. The generation mechanism, composition, and analytical expressions of short-circuit current were proposed. DFIG models were constructed to calculate the initial and steady-state short-circuit current. Simulation and experiment were performed to verify the efficacy of the proposed analyses.