Additional Mechanical Torque Coefficients of Hydro Turbine and Governor System

Abstract

The change of mechanical torque is usually ignored in small disturbance of power systems, which means that influences of the hydro turbine and governor system (HTGS) have been ignored. The disturbance characteristics of the hydro turbine generating units including the HTGS is studied based on torque coefficients method in this paper, and calculating method and expressions of torque coefficients of the HTGS are given. The additional mechanical damping produced by the HTGS can be expressed as DtΔω, therefore, it can be merged into the damping item in the motion equation of generator, that means that its action is equivalent to modify damping coefficient D. Using a case, the analysis and calculation method are introduced, and several conclusions are given.