Electromechanical transient modeling of AC/DC hybrid system incorporating VSC based DC grid

In this paper, the electromechanical model of VSC HVDC-integrated AC/DC hybrid system is established. The VSC station model is comprised of the physical model and the control model. In the mathematical control model, the inner current-loop regulator, the outer loop regulator, the modulation and the phase-lock loop are taken into consideration. The proposed model is validated through the simulation of a 5-port VSC-HVDC integrated IEEE 39 system with DIgSILENT. The transient-stable closed-loop control algorithm is utilized and the stability study is performed, demonstrating the accuracy of the proposed model and the effectiveness of the control scheme in hybrid systems.