Generation of second harmonic component of fault current in a doubly‐fed induction generator and mitigation measures for transformer protection

The transient characteristics of short-circuit current (SCC) in doubly-fed induction generator (DFIG) are quite different from the widely researched conventional synchronous machines. However, second harmonic SCC that impact reliability transformer protection have not been accurately analysed. This paper presents generation mechanism DFIG by deducing dynamic response rotor-side converter, with particular attention to influences voltage drop, component stator voltage, frequency coupling, and deviation phase-locked loop. When grid fault occurs, terminal sag leads fluctuations active power, then converter power fluctuation coupling abc reference frame. And injected into disturbance term loop, which, turn, affects current. Based on analysis, mitigation measures for proposed. Simulations implemented verify theoretical analysis.