Optimal Controller Design for Interconnected Power Networks With Predetermined Degree of Stability

A novel procedure for the design of an optimal controller with a predetermined degree of stability to enhance damping of interarea oscillations in interconnected power networks is presented in this paper. The proposed approach includes a feedback controller, which is independent of internal disturbances as a stabilizer. A tuning parameter is also provided, which treats load changes as disturbances. The gains of the proposed controller are calculated based on moving the dominant poles to the left on the S plane to obtain a desired stability margin and provide a prescribed degree of stability. In order to better validate the performance of the proposed controller, a multiarea power system is considered with different step load changes that are applied successively in simulations. The time responses and eigenvalue analysis are presented and discussed thoroughly. It is shown in the results that the developed optimal controller can effectively damp the frequency and tie-line power deviations in interconnected power systems.