Ahmad Mostajabi - Electrical Engineering Department, Khomeinishahr Branch, Islamic Azad University,P.O.Box 84175-119, Isfahan, Iran
Shahrokh Shojaeian - Electrical Engineering Department, Khomeinishahr Branch, Islamic Azad University,P.O.Box 84175-119, Isfahan, Iran
Mehri Lotfi - Electrical Engineering Department, Khomeinishahr Branch, Islamic Azad University,P.O.Box 84175-119, Isfahan, Iran

This paper proposes a multiple-model adaptive control (MMAC) method in order to improve dynamic stability of a multi-machine power system with hydro-turbo generators during a sudden change in the system loads. A bank of several classic second order models are used for each generator. Each model is linearized around an expectable operating point of the generator. A proper PI controller is designed for each model. The probability of each model is calculated based on closeness of its response to the real plant response with a Bayesian approach and suitable weights are assigned to each controller. The MMAC algorithm could identify the dominant post disturbance dynamics and switch to the appropriate controller to achieve the desired performance. Some simulation results are presented in order to verify the validity and effectiveness of the proposed control approach.

Dynamic stability, multi-model control, Low frequency oscillations, robustness