Mitigation of sub-synchronous control interaction of a power system with DFIG-based wind farm under multi-operating points

This study presents a probabilistic design of a power system stabiliser (PSS) for doubly-fed induction generator (DFIG) converter and investigates its potential capability in mitigating the sub-synchronous control interaction (SSCI) at multi-operating points. The aim is to improve the probabilistic sub-synchronous stability of the system with wind farm penetration. In this study, participation factors are obtained to identify the SSCI strong-related state variables and major control loops, which are used for the preliminary siting of the DFIG-PSS. Probabilistic sensitivity indices are then employed for accurate positioning of the PSS, selecting the input control signal and optimising the PSS parameters. The effectiveness of the proposed approach is verified on a modified two-area power system. The results show that the designed DFIG-PSS is capable of improving probabilistic small-signal sub-synchronous stability of the system at multi-operating points and its performance is better than a DFIG-PSS designed with the general small-signal method.