Feasibility study to damp power system multi-mode oscillations by using a single FACTS device

To damp power system multi-mode oscillations, the commonly-used method is to arrange multiple decentralized stabilizers, such as PSS (Power System Stabilizer) and FACTS (Flexible AC Transmission Systems) stabilizers. In order to overcome the problem of interactions between stabilizers, coordinated design of multiple decentralized stabilizers has been proposed to simultaneously set parameters of all stabilizers. However, in practice it could be very difficult to implement the coordinated design of multiple stabilizers. This is because those stabilizers are often at different geographical locations in a power system and cross-location simultaneous field tuning of stabilizers' parameters is a tremendous task due to their interactions. Hence this paper proposes a novel scheme of damping power system multi-mode oscillations by using a single FACTS device and presents the results of feasibility study of the proposed scheme. It is demonstrated that multiple stabilizers can be arranged in a single FACTS device to effectively damp power system multi-mode oscillations. Under this scheme, multiple stabilizers are at a same geographical location in the power system and hence their parameters can be tuned simultaneously in coordination in the field. In the paper, three examples of multi-machine power systems installed with a UPFC (Unified Power Flow Controller), a STATCOM (Static Synchronous Compensator)/BESS (Battery Energy Storage System) and a MUPFC (Multiple-terminal UPFC) respectively are presented. Parameters of multiple stabilizers are designed in coordination by using a newly appeared method of optimisation-artificial fish swarm algorithm. Simulation results in the paper are compared with those obtained from applying the conventional scheme of decentralized control involving multiple PSSs. They demonstrate and confirm the feasibility of proposed scheme in the paper.