Nonlinear Robust Control For Turbine Main Steam Vavle Of Multi-machine Power System

With the development of economy, the improvement of living standard and theincreasing power demand, it is necessary for us to research the transient stability problem ofmulti-machine power system. However, due to the application of new technology and theincreasingly complex of grid structure, the power system stability has attracted a great deal ofresearch attention in recent years. Therefore, a good stability controller is designed so as toimprove overall operational characteristics and stability of power system. Steam valve controlcan be useful to improve the power receiving capability, and the transmission capacitybetween the power plants. Turbine main steam valve control has played an important role innot only improving power system transient stability but also restraining the low-frequencyoscillation and bettering dynamic performance.In this paper, the nonlinear robust control problem of multi-machine power system withturbine main steam valve control is addressed by the means of adjusting steam vavle based onLyapunov theory and backstepping control. And fuzzy logic system is used to approximate theunknown function due to coupling of unknown subsystem in the multi-machine power systemare taken into consideration. Firstly, the unknown damping coefficients are taken intoconsideration based on the third-order model of the multi-machine power system with steamvalve control, the decentralized robust controller is designed by the method of direct fuzzybackstepping. Secondly, external interferences are taken into consideration and the robustcontroller is designed by the method of robust H∞.Lastly, the transient response speed andcontroller gain performance indicators of the system achieve comprehensive balance by usingclass-K function. Matlab simulation results manifest the validity of designed method.