Local Control of AC/DC Converters for Frequency Support Between Asynchronous AC Areas

This paper proposes a novel control scheme for frequency support among asynchronous AC areas through HVDC grids. It is based on local controllers, each acting on a voltage source converter, using locally available measurements only, and supporting frequency of the adjacent AC area after a significant disturbance. The controller is combined with the existing DC voltage droop technique and is inspired of Model Predictive Control, taking into account various constraints. The coordination of the proposed control scheme with the existing secondary frequency control of an AC area is also discussed. Examples obtained from a test system with a five-terminal DC network connecting two asynchronous areas demonstrate the effectiveness of the proposed control scheme.