A non-linear decentralized control of multimachine power systems based on a backstepping approach

Abstract

Power system requires high-performance control techniques due to their elevated complexity, high nonlinearity and almost continuously time-varying nature. Also, power systems are often subjected to small and large disturbances. To enhance the multimachine power system stability, a new approach to designing decentralized nonlinear control scheme is proposed. The approach seeks first build a novel mathematical model of multimachine power systems. The main characteristic of this model is that interactions between generators and changes in operating conditions are represented by time-varying parameters. More important, those parameters are update online, using only local measurements. Second, it develops a decentralized controller for the transient stabilization and voltage regulation. The controller consists of two controllers, known as the terminal voltage regulator and rotor speed stabilizer. The methodology adopted is based on backstepping design strategy. The proposed stabilizing feedback laws for the power system are shown to be globally asymptotically stable in the context of Lyapunov theory. Case studies are achieved in a two-area four machine power system to verify the effectiveness of the approach. Numerical results are presented to illustrate the usefulness and the performance of the proposed control scheme, under different contingencies.