Suppression of low frequency and shaft oscillations of AC/DC hybrid power system with integrated wind farm under multi‐operating points

This paper focuses on mitigating low frequency and shaft oscillations of AC/DC hybrid power system with integrated wind farm under multi‐operating points. A probabilistic method based on Gram‐Charlier expansion with a hybrid algorithm using moments and cumulates is applied to cope with the issue of oscillations over a wide range of operating points. For low frequency oscillation modes, the damping contribution of DC modulation (DCM) controller and power system stabilizer (PSS) is compared. As for the shaft oscillation mode, the principle analysis and damping contribution of shaft stabilizer are investigated. The damping contribution to modes of low frequency and shaft oscillation of damping controllers is investigated on a five‐machine two‐area AC/DC power system. The major contributions of this paper are (a) investigation of the shaft oscillation, including principle analysis and its suppression measure and (b) application of the probabilistic method to enhance the controllers' capability of adapting to the AC/DC hybrid system over a wide range of operating points.