Impact of VSC-HVDC Reactive Power Control Schemes on Voltage Stability

Voltage Source Converter based High Voltage Direct Current (VSC-HVDC) links arc popular for transferring power over long distances due to their cost and flexibility, particularly their capability for reactive power control. This paper focuses on the impact of VSC-HVDC on voltage stability in AC systems, particularly how the VSC control scheme affects voltage stability. A variety of commonly proposed reactive power controls are implemented and analysed including reactive power (Q) control, AC voltage (V-AC) control, and V-AC - Q droop control. The effects of controller limits and deadbands are also investigated. The results show the advantages and limitations of the different control schemes tested, thereby helping to define which type of control is most appropriate depending on the system requirements.