Feedback-linearization and feedback-feedforward decentralized control for multimachine power system

In this paper a decentralized nonlinear controller for large-scale power systems is investigated. The proposed controller design is based on the input–output feedback linearization methodology. In order to overcome computational difficulties in adopting such methodology, the overall interconnected nonlinear system, given as n-order, is analyzed as a cascade connection of an n1-order nonlinear subsystem and an n2-order linear subsystem. The controller design is obtained by applying input–output feedback linearization to the nonlinear subsystem and adopting a tracking control scheme, based on feedback–feedforward technique, for the linear subsystem. In the assumed system model, which is characterised by an interconnected structure between generating units, a decentralised adaptive controller is implemented by decentralizing these constraints. The use of a totally decentralised controller implies a system performance decay with respect to performance when the system is equipped with a centralised controller. Fortunately, the robustness of the proposed controller, based on input–output feedback procedure, guarantees good performance in terms of disturbance even when disturbances are caused by decentralization of interconnection constraints. Test results, provided on the IEEE 30 bus test system, demonstrate the effectiveness and practical applicability of proposed methodology.