A review on fatigue damage mechanism in hydro turbines

Well knowing a good-running hydraulic turbine has important operational and financial benefits to those who operate a plant. Fatigue damage is the most fundamental failure type of hydraulic turbines. Existing flaws due to fatigue and their risk limit the operating time of a unit. Some plants have been temporarily shut down for up to a month and sometimes longer to repair these fatigue-induced damage, which has resulted in enormous economic losses. Fatigue problems must be solved or effectively prevented to ensure that turbine units run safely and steadily within their design life. This paper reviews loading features and some key issues (e.g. different load operations, start-up, emergency shut-down, load rejections, and runaway) on the fatigue damage, and provides the latest information about different prediction approaches. At last, it also attempts to present an overview of the complete failure modes, therefore other types of failure including cavitation, erosion and ingested bodies are introduced briefly.