Analysis and Improvement of the Stability of a Hydro-Turbine Generating Unit With Long Penstock

The influence of water column elasticity on the stability limits of a hydro- turbine generating unit with long pen-stock operating on an isolated load is investigated. D-decomposition method is used for deriving the stability regions including the elastic water column. It has been shown that a modified water column compensator enhances the stability regions and dynamic performance considerably.