Decentralised nonlinear H∞ control for stability enhancement in power systems

A method for designing the decentralised H∞ excitation control of a generator in power systems is presented. The proposed controller is utilised to damp inter-area oscillations and enhance power system stability. The decentralised controller design procedure for nonlinear systems is presented using the Hamilton-Jacobi inequality approach. The control is local or decentralised, in the sense that the controller depends only on the information available locally. The effectiveness of the proposed decentralised H∞ controller is demonstrated through digital simulation studies on a two-machine power system. The digital simulation studies are conducted using the PSCAD/EMTDC software package. The simulation results show that the controller contributes significantly to the damping of inter-area oscillations and the enhancement of power system stability under a wide range of operating conditions.