Research On Intelligent Control Hydraulic Turbine Governor System Based On PCC

According to the present problems and developing tendency of hydraulic turbine governor, four main issues of this field are studied in this paper. The content include hydraulic control system, frequency measurement unit, stability of the discrete control system, optimization of control parameters and self-adjusting PID control strategy based on fuzzy logic. Several main achievement and results are obtained and shown as follows:The electric-hydraulic pilot valve driven by step-motor is firstly proposed, which solves the problem that the electric-hydraulic converter of hydraulic turbine governor hydraulic servo is prone to be stuck and blocked and improves the systemic stability greatly. Based on it, a new-style step-type electric-hydraulic servo is developed which simplifies the structure and improves the reliability of the governor, and the mathematical model and its stability control equation are obtained.A new method, which uses shaping circuit and programmable computer controller with appropriate software to measure frequency, is initially applied which overcomes the problems of low reliability and slow responding process of traditional frequency measurement unit, improves the reliability and dynamic quality of frequency measurement and expedites the responding speed effectively. The sample industrial controller of PCC step-type hydraulic governor using this method is proved to be successful by practical operation in hydropower stations.Based on modeling and analyzing the discrete mathematic model of hydraulic turbine governor system, the edge equation of stable domain of the discrete control system is obtained. According to this equation, the stable domain is specified. Compared with continuous system, the changing rules and characters of the discrete system are found, which provide the theoretic foundation for researching the control strategy and the parameter adjustment of discretecontrol system of the hydraulic turbine governor.In addition, a new improving genetic algorithm with the alterable intercross probability and mutation probability to optimize the parameters of hydro turbine governor is presented. The simulation result doesn' t suggest that it depend on the initial parameter value of the system and the searching efficiency can be ameliorated. At the same time, it has strong robustness and is an excellent PID optimization method.Finally, referring the intelligent control theory, the self-adjusting parameter PID control strategy based on the fuzzy logic rules is introduced. Combining the fuzzy logic and traditional PID control, it makes governor more adaptive to the real operation conditions. Since the fuzzy reasoning rules are difficult to make, the improving genetic algorithms is applied to optimize the fuzzy reasoning rules and thus the excellent fuzzy reasoning rules can be obtained. The simulation result shows that the self-adjusting PID control strategy based on fuzzy reasoning rules is more available.