Short circuit ratio analysis and voltage stability control of power system with DFIG-based wind turbines

In order to improve the assessment of the voltage support capability for new energy grid integration, this paper first establishes a third-order virtual synchronous generator dynamic model. Then, by analyzing the phase relationship, a new short circuit ratio index considering the short circuit capacity of new energy sources is proposed. Secondly, based on the relationship between the new short circuit ratio and voltage support strength, a voltage active support control strategy based on virtual transient reactance is proposed. Finally, through simulation tests, the results show that the new short circuit ratio index can effectively reflect the voltage support capability of the grid connection point, and the effectiveness of the proposed control strategy is verified.