Research Of General Controller To Hydro-Generator Sets In Isolated Grids

Synchronous generator excitation systems and hydro turbine governors are very important control equipments in power plants. They play key roles to ensure the electricity quality, and the power system to run safely and stably. Excellent control systems of hydro-generator sets not only could guarantee the generator running safely, offer the qualified electric power, but also improve the static stability, dynamic stability and transient stability of the power system.During researching the hydro-generator set control system, the excitation system and the governor are studied respectively. Some scholars have worked out the general controller, but their objects are machines in the Single Machine-Infinite Bus System (infinite grids), that is, the rotate speed of the hydro-generator set or the frequency of the grids is invariable. This paper based on the general control in isolated grids(small grids), brings forward using the nonlinear inverse system method to solve the control problem of the rotate speed of the hydro-generator set or the frequency of the grids variable. After introduction of the hydro-generator set movement equation, the state equation of stand-alone system is presented. It is expressed to rank a integral inverse system figured with feedback methods, using inverse system method. Then, it is equalized to the fake linear system with linear transfer relations. Finally, the integrative system design is accomplished using the theory of linear optimization control.Depending on SimPowerSystems in MATLAB, the paper constructs and simulates the isolated grids hydro-generator set's model, at the same time,the control laws are used to control hydro-generator sets under some conditions. The results show that the general controller responds rapidly under the disturbance, enhances the power system dynamic performance, and improves modulation precision. The general control rules based on the nonlinear inverse system method with simple calculation processes and clear conceptions have optimistic future, if it is used to control hydro-generator sets in isolated grids.