Robust controllers for multimachine power systems

The paper describes a fresh look at designing decentralised stabilisers in multimachine power systems utilising shaft speed variations as input. The design technique has been extended to power system stabilisers using shaft speed and electric power. The main objective is to enhance dynamic stability of a power system by applying PSSs with parameters so evaluated that all the unstable or weakly damped mechanical modes´ eigenvalues have desired values. The robustness of the closed loop system is considered with the loop broken at different input points. The usefulness of the above method is illustrated through a numerical example corresponding to a three machine system. Simulation results show that the proposed controllers yield good system dynamic performance in response to step disturbances