Coordinated modulation strategy considering multi-HVDC emergency for enhancing transient stability of hybrid AC/DC power systems

This paper presents a multi-HVDC emergency coordinated modulating strategy to enhance the transient stability of hybrid AC/DC power systems. First, the main factors that affect the unbalanced energy distribution during a fault are analyzed, and the dominant generators are determined online. Next, considering the influence on both generators in the sending and receiving ends, the assessment index that evaluates the effects of DC power support is established. On the basis of this, a dynamic DC power support strategy is put forward, and the DC support sequence table is promptly updated by the changing dominant generators. The AC/DC hybrid power system with multi-DC lines is built and used as a test system. The simulation results of different scenarios demonstrate that the proposed method could follow the dominant generator dynamically and adjust the DC participating in modulation to enhance the transient stability effectively and quickly.