Aiming at the difficulty of oscillation suppression of the grid-connected direct-drive wind farms via voltage source converter based multi-terminal HVDC (VSC-MTDC) transmission system under sending end fault scenarios

a dynamic energy model of the system is established in the paper

the mechanism of the system’s oscillation instability is revealed and an oscillation suppression strategy was designed. Firstly

based on the dynamic characteristics of the control links

the system is divided into several subsystems

and a dynamic energy model including stored energy

dissipation energy and interaction energy is constructed. Further

the magnitude and direction of each interaction energy item are calculated

the influence of each interaction energy item on the system’ stability is quantitatively assessed

and the instability mechanism is revealed. On this basis

the additional control links are designed to inhibit the propagation of oscillation energy. Finally

the accuracy and effectiveness of the proposed method are verified by hardware-in-loop tests. From the results

the proposed oscillation suppression method has good oscillation suppression effect in different oscillation scenarios. And the proposed method can serve as a new universal solution for suppressing oscillation.