Coordinated Voltage - Reactive Power Control in Networks with Embedded VSC HVDC Lines

This paper presents an approach for a coordinated voltage - reactive power control using VSC HVDC lines embedded in large AC networks. The proposed control algorithm incorporates the HVDC into the overall Var dispatch strategy of the network. Additionally, it is able to fulfil the dynamic voltage support requirements following grid short circuits. The models of these hierarchical two-stage controllers have been described in detail and approaches for coordination of their operation explained. Simulation examples demonstrate the disturbance as well as the reference tracking behavior of the controller.