A Voltage‐Sensitivity‐Based Incremental Reactive Power Control Strategy for Mitigating Repeated LVRT in PMSG‐Based Wind Farms

ABSTRACT

The increasing penetration of wind power has accentuated weak‐grid characteristics. Consequently, the coupling between the low‐voltage ride‐through (LVRT) behaviour of permanent magnet synchronous generator (PMSG)‐based wind turbines and weak grids can trigger the repeated LVRT phenomenon. In severe cases, this leads to large‐scale wind turbine tripping, jeopardising system security and stability. Existing studies predominantly focus on mechanism analysis, while suppression methods remain scarce and suffer from large voltage fluctuations and insufficient adaptability. This paper proposes a voltage‐sensitivity‐based incremental reactive power control strategy for mitigating repeated LVRT. Based on the weak sending‐end model of a PMSG‐based wind farm and mechanism analysis, the equivalent parameters of the sending‐end system are obtained through a combination of offline table lookup and online identification. The repeated LVRT risk index and real‐time voltage sensitivities are then calculated, based on which incremental feedback regulation is applied to a static var generator (SVG) or energy storage system. The proposed strategy blocks the recovery–LVRT switching cycle while suppressing transient voltage fluctuations during active power recovery, and is adaptive to variable wind speed conditions and parameter deviations. Controller hardware‐in‐the‐loop (CHIL) test results on the RT‐LAB platform demonstrate that the proposed strategy mitigates repeated LVRT, reducing the maximum transient voltage fluctuation from 0.17 to 0.04 p.u., a reduction of 76%, while achieving superior voltage control performance over existing methods.