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Evaluation of Acceleration Effect of Ancillary Services on Cavitation and Fatigue of a Water Turbine in Pumped-Storage Plants

부수적 서비스 제공에 따른 양수발전소 수차의 캐비테이션 및 피로에 대한 가속효과 평가

  • Received : 2016.07.21
  • Accepted : 2016.11.22
  • Published : 2017.03.01

Abstract

Several maintenance issues related to cavitation erosion and fatigue cracks in the water turbine subcomponents of pumped-storage plants, such as a runner and a draft tube, have been reported in the past. Generally, the pumped-storage plants provide ancillary services, such as black-start and system stabilization. The ancillary services are responsible for cyclic low opening operation of the guide vanes. It has been empirically established that this low opening operation further damages the water turbine subcomponents. In this study, the acceleration effect of the low opening operation on the cavitation erosion and fatigue of the water turbine is quantitatively assessed through finite element flow analysis, finite element stress analysis, and fatigue analysis. As a result of the assessment, it is identified that the cavitation potential increases and the turbine efficiency decreases with a decrease in the opening of the guide vane. Also, the low opening operation has an insignificant effect on the fatigue even though it increases the maximum stress values at the runner blade roots.

Keywords

Pumped-Storage Plant;Water Turbine;Runner;Guide Vane;Low Opening Operation;Ancillary Service;Cavitation;Fatigue;Finite Element Method

Acknowledgement

Supported by : 기초전력연구원

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