Abstract :
Very old hydro-powerplants are mostly no longer economical because of lower availability, reliability and efficiency; increased maintenance, expensive operation due to staff requirements and noneconomical exploitation of the existing water power. For such plants, modernisation has to be considered for the following reasons: to increase the technical performance and decrease expenditures for operation and maintenance; technical progress and innovation for possible improvements; and to change the external utilisation conditions of the plant. A renewal of a plant can be made by replacing or overhauling the main components such as gates, valves, turbines, generators, transformers and switchgear, by modernising the control, instrumentation and information system, or both simultaneously
