Robust Nonlinear Excitation Control For Multimachine Power System

With the continuous expansion of the capacity and scale of power system putting forward more strict requirements to power system stability, excitation control, as one of the effective ways to improve power system stability, its research has received extensive attention of scholars. Due to the influence of different interference during power system operation, the designing of excitation controller with strong robustness is more realistic to improve power system stability.Firstly, considering the influence of uncertain parameters within system, the parameter adaptive law and control law are designed for a nonlinear system with low triangular structure by the method of combining traditional adaptive backstepping method with sliding mode variable structure control method. In addition, considering the influence of external disturbance, the control law with strong robustness is designed by the method of combining L2 gain interference suppression method with the former method.Secondly, the research of multi-machine power system excitation control is carried out. Due to the damping coefficient of synchronous generator is difficult to be accurately measured, the damping coefficient is regarded as an uncertain parameters. That is to say, considering the influence of parameter disturbance within system, the excitation controller and parameter adaptive law are designed for multi-machine power system by using the adaptive backstepping sliding mode method. In addition to the internal parameters perturbation, the influence of external disturbance is greater to the stable operation of power system. Considering the internal and external disturbance at the same time, the robust excitation controller is designed for multi-machine power system by using the method of combining adaptive backstepping sliding mode method with L2 gain interference suppression method. Due to the response time of the excitation system has a great influence on the transient stability of power system, the K class function is introduced into the new method on the basis of the traditional backstepping method to improve the response speed of the excitation control and the convergence rate of state variables and the fast robust excitation controller is designed. Finally, the above excitation controllers are simulated and the simulation results show that the designed controller has significant effect to improve the stability of power system.