Case 52: Failure of a Turbine Vane in a Hydroelectric Power Plant

A generating system in a hydroelectric power plant was shut down to investigate an abnormal sound coming from one of the turbines. A piece of metal that had broken off one of the vanes on the runner was found in the tail race and was subsequently examined along with the runner. Based on the fracture characteristics, as described in the report, the vane failed in fatigue due to a crack that initiated in an area of stress concentration.