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

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

  • 투고 : 2016.07.21
  • 심사 : 2016.11.22
  • 발행 : 2017.03.01

초록

런너, 흡출관 등 양수발전소 수차 부속기기들에 캐비테이션 침식과 피로 균열 등의 손상 발생과 관련하여 많은 정비 사례들이 보고되고 있다. 양수발전소는 급전, 전력계통 안정 등과 같은 부수적 서비스를 제공한다. 이러한 부수적 서비스는 가이드 베인을 작게 열고 운전하는 저개도율 운전을 반복적으로 자주 수행하게 한다. 이러한 저개도율 운전은 수차 부속기기의 손상을 가속시키는 것으로 경험적으로 알려져 있다. 본 연구에서는 양수발전소의 가이드 베인 저개도율 운전이 수차의 캐비테이션과 피로를 가속시키는 효과를 유한요소 유동/응력 해석 및 피로 해석을 통해 정량적으로 평가한다. 평가 결과, 가이드 베인 개도율이 작을수록 캐비테이션 발생 가능성과 수차 효율 저하 가능성이 증가하며, 런너 블레이드 루트부에 최대 응력값을 증가시킴에도 불구하고 저개도율 운전이 피로수명에 미치는 영향은 미미함을 확인하였다.

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.

키워드

참고문헌

  1. Korea Hydro Nuclear Power Company, 2011, Development of Methodology for Lifetime Management and Modernization Plan Establishment of Pumped Hydro Storage Power Plant Equipments.
  2. Korea Electric Power Corporation, 2004, Practices of Hydropower Plant.
  3. Korea Electric Power Corporation and Korea Nuclear & Hydraulic Company, 1996-2006, Annual Reports for Hydropower plants.
  4. EPRI, 2001, Hydropower Technology Roundup Report: Accommodating Wear and Tear Effects on Hydroelectric Facilities Operating to Provide Ancillary Services, EPRI TR-113584-Vol.4.
  5. EPRI, 1984, Hydropower Reliability Study, EPRI EM-3435.
  6. Kim, J.S., Kwon, H.C., Song, B.H. and Kwon, C.S., 2009, "Development and Application of the Methodology to Establish Life Extension and Modernization Plan of Aged Hydropower Plants," Trans. Korean Soc. Mech. Eng. A, Vol. 33, No. 10, pp. 991-1186. https://doi.org/10.3795/KSME-A.2009.33.10.991
  7. Kim, J.S., 2010, "Optimization of Preventative Maintenance Cycle for Equipments of Pumped-Storage Power Plant by Taking into Account Reliability and Economical Efficiency," Trans. Korean Soc. Mech. Eng. A, Vol. 34, No. 9, pp. 1137-1338. https://doi.org/10.3795/KSME-A.2010.34.9.1137
  8. Kim, J.S. and Kim, S.N, 2012, "Evaluation on the Effect that Low Opening Operation of Guide Vanes in Hydropower Plants Accelerates Wear on Guide Vane Bearing Bushing," Trans. Korean Soc. Mech. Eng. A, Vol. 36, No. 10, pp. 1267-1274. https://doi.org/10.3795/KSME-A.2012.36.10.1267
  9. Jones, D.I., Mansoor, S.P., Aris, F.C., Jones, G.R., Bradley, D.A. and King, D.J., 2004, "A Standard Method for Specifying the Response of Hydroelectric Plant in Frequency-Control Mode," Electric Power System Research, Vol. 68, pp. 19-32. https://doi.org/10.1016/S0378-7796(03)00152-4
  10. Siwani, Y.D., 2008, Dynamic Stress Assessment in High Head Francis Runners, Master Degree Thesis, Lulea University of Technology, Sweden.
  11. Liu, S, Zhang, L., Nishi, M. and Wu, Y., 2009, "Cavitating Turbulence Flow Simulation in a Francis Turbine Based on Mixture Model," Journal of Fluids Engineering, Vol. 131, No. 5.
  12. Korea Western Electric Power Company, 1990-2010, Preventative Maintenance Reports for Samrangjin Unit 1 & 2.
  13. Hitachi and Korea Tsukuba, 2010, Precision Diagnosis and Lifetime Assessment Report for Samrangjin Unit 1.
  14. Hitachi, 1984, Instruction Manuals for Pumped-Turbine of Samrangjin Unit 1 & 2.
  15. Dassault Systems, 2010, Solidworks User's Manuals, Ver.6.10.
  16. Escaler, X., Equsquiza, E., Farhat, M., Avellan, F. and Coussirat, M., 2006, "Detection of Cavitation in Hydraulic Turbines," Mechanical Systems and Signal Processing, Vol. 20, pp. 983-1007. https://doi.org/10.1016/j.ymssp.2004.08.006
  17. ASME Boiler and Pressure Vessels Committee, 2007, ASME B&PV Code, Sec. III, Subsection NB, NB-3200.