Transient Voltage Stability Analysis of Doubly-fed Induction Generator Based on Singularity Principle

As we all know, the transient voltage of the double-fed induction generator (DFIG) will lead to current saturation and then automatic off-grid, which is detrimental to the stability of the power grid under fault. With more occurrence of voltage instability accidents, the voltage stability of wind farms has been paid more attention. The singularity of differential algebraic equations (DAEs) is closely related to transient voltage instability. Jacobian matrix is generally used to judge the instability of the system in current study, but it is difficult to calculate in practice. Therefore, this paper studies the mechanism of transient voltage instability of DFIG from the perspective of DAEs mathematical model, deduces phase angle limit of DFIG, which can be used as a practical index to judge the stability of the system, and verifies that the phase-locked loop (PLL)is the key reason for the instability of grid following DFIG by simulation in Simulink.