DFIG-SMES Coordinated Control Strategy for Improving Small Signal Stability of Multi-machine System

Large scale wind farm integration has a great impact on the safe and stable operation of the power system, so it is increasingly important to improve the small signal stability of the power system with a wind farm. In this paper, a coordinated control method of the doubly-fed induction generator (DFIG) and the superconducting magnetic energy storage (SMES) is proposed to improve the small signal stability of the multi-machine power system. Starting from the actual access position of a wind farm in the power grid, the relationship between the change of electromagnetic power of the synchronous machine and the DFIG access is deduced by modifying and shrinking the node voltage equation of the power system with the wind farm. On this basis, the damping effect of the power characteristics of the wind farms on the oscillation mode of the system is analyzed according to the complementary group inertia weighted average angle relative value transformation rule, and the DFIG-SMES power compensation coordinated control strategy is proposed to improve the small signal stability of the system. The simulation results show that in the small disturbance dynamic process of the system, by reasonably adjusting the exchange power of SMES, the positive damping effect of the wind farm parallel node on the system is enhanced, and the small disturbance stability of the system is improved. © 2022, Power System Technology Press. All right reserved.