Standardization as Prevention of Fatigue Cracking of Hydraulic Turbine-Generator Shaft

Design, construction and operation of Hydropower plants are complex tasks. A large number of details must be carefully considered, coordinated and executed in order that the projects achieve safe and economical operation. Corrosion fatigue cracking of horizontal turbine-generator shafts has been thoroughly examined and discussed in the last twenty years. As a result of corrosion fatigue cracking, in most cases, catastrophic failures occurred. Excessive damages of vertical shaft couplings, discovered during turbine rehabilitation , have raised concerns regarding the value of nut guard application, as well those of corrosion damage rectification and repair techniques . Because of the consequences of shaft failure the following paper will provide the rationale for contribution to the respective standard.