Coordinating the DC Power Injections of a Multiterminal HVDC System for Dynamic Control of AC Line Flows

As more dc terminals, in the form of links or multiterminal systems, come into operation, the opportunity for controlling ac line flows using the injected dc powers increases. This paper describes a study undertaken to determine the feasibility of using an on-line method to coordinate the dc injections of a multiterminal dc system to dynamically control the power flows in certain ac lines of an integrated ac-dc power system. The proposed controller can be used to steer and to regulate the power flows, and also to damp the power oscillations in these ac lines. The effectiveness of the controller is demonstrated using a transient simulation program.