Nonlinear Robust Control For Multi-Machine Power System With FACTS

With the rapid development of economy,great changes have taken place in power system.The scale of power system is larger and larger,and the structure is more and more complex.As an efficient and flexible device,FACTS provides a new regulation mode for the stable operation of multi-machine power system on the premise of ensuring economic benefit.Therefore,the transient stability problem of multi-machine power system with FACTS is widely concerned.Based on the improved backstepping method,combined with adaptive control,sliding mode control and L2 gain interference suppression theory.This paper studies the transient stability of multi-machine power system,including STATCOM,SVC and TCSC.The main results are as follows:(1)The transient stability of multi-machine power system with STATCOM is studied.Firstly,considering the uncertainty of damping coefficient,the improved adaptive backsteppi--ng method and sliding mode control are used to design the nonlinear robust controller.Then,considering the internal and external interference,using the improved adaptive backstepping method,and combining with the adaptive sliding mode control to design a continuous sliding mode term to suppress the interference,the nonlinear robust controller is designed.(2)Considering the "coefficient expansion" problem of backstepping method,the transient stability of multi-machine power system with SVC is studied.Firstly,considering the uncertainty of damping coefficient,and using the improved adaptive backstepping method and adaptive sliding mode control,the nonlinear robust controller is designed;Then,considering further the disturbances in the system,basing on the improved adaptive backstepping method and adaptive sliding mode control,and adding a robust sliding mode term to suppress the external disturbances,the nonlinear robust controller is designed.(3)In order to improving the estimation accuracy of adaptive control,we introduces a kind of immersion and invariant adaptive control without following certainty equivalence principle.First of all,considering the uncertain parameters under the condition of the multi-machine power system with TCSC model,and using the improved backstepping method,immersion and invariance adaptive control and adaptive sliding mode control which can inhibit the problem of "expansion coefficient",the nonlinear robust controller is designed.Then,considering the external disturbance,the L2 gain interference suppression theory is adopted to deal with the interference,and the nonlinear robust controller is designed.