Study On Multi-Index Nonlinear Integrated Control Strategy For Kaplan Turbine

Water turbine control system is a complex nonlinear, mechanical and electrical integrated control system。 Because of the large moment of inertia of the unit and the turbine control system has the strongly nonlinear, the dynamic quality of the control target has a great influence, making the system stability analysis and parameter setting with great difficulty. In the field of power system, nonlinear control theory can be applied in the study of specific equipment, such as excitation control system, speed governing system and integrated control system of hydraulic turbine, nonlinear control theory has wide application prospects in the hydraulic turbine control system. Currently, domestic and foreign scholars have a thorough research on Francis turbine control system, and not much on the study of Kaplan turbine control system.Therefore, this paper mainly investigates and analyzes the control system of Kaplan turbine using nonlinear control theory.Firstly, on basis of analysing the mechanical and electrical characteristics of Kaplan turbine, established the fifth-order nonlinear model of speed control system of Kaplan turbine. According to the control method applied in actual engineering, proposed a single variable tracking control strategy (Single-Variable Tracking Control of Kaplan turbine, SVTC). Simulation results show that:the proposed model of speed governing system reflects the nonlinear characteristics of the turbine units effectively, as well as verify the validity and superiority of SVTC control strategy.Secondly,In order to overcome the blade angle control lag time and location in the guide vane opening,reduce the dynamic process of adjustment time,improve the utilization of the axial flow paddle turbine hydropowe,the traditional single variable speed governing system was improved by the two variables model which can control guide vane opening and Blade angle simultaneous. Meanwhile, a strategy of Multi-Variable Coordinated Control of Kaplan turbine (Multi-Variable Coordinated Control of Kaplan turbine, MVCC) was presented. Simulation results show that:The improved model is effective and appropriate, as well as verify the validity and superiority of MVCC strategy.Ultimately, this paper was established the sixth-order nonlinear model of integrated control system of Kaplan turbine. Aimed at the rigid water hammer effect for Kaplan turbine, a nonlinear controller, which was based on the Multi-index nonlinear control theory, was designed. Simulation results show the validity of the proposed control strategy.