PSI - Issue 48

Evgeniia Georgievskaia / Procedia Structural Integrity 48 (2023) 310–317 Georgievskaia / Structural Integrity Procedia 00 (2019) 000 – 000

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1. Crack formation in some welded areas of hydraulic units’ supporting structures is a structure aging natural result under normal operating loads and is inevitable even in case of meeting all operating conditions and with high quality of the repairs. 2. Supporting structure uneven load distribution and high local stresses in areas with the most stress concentration are usually not considered during hydraulic units’ design stage, which results in premature and intensive cracking of the supporting structures. 3. Supporting structure cracks reduce efficiency earlier modernization effectiveness and limits the HU lifetime overall by reducing inter-maintenance periods and increasing the amount of recovery repairs. 4. Old units’ research results help develop effective measures to reduce crack formation intensity and ensure LSS and HU reliable operation in general: technological recommendations for recovery repairs in case of cracks found in LSS, inter-overhaul LSS inspection recommendations, LSS structure reinforcement recommendations. For new equipment being designed, the results presented will help taking factors reducing the reliability and lifetime of the structure into account, as well as ensuring HU long-term safe operation considering operating characteristics. For each unit these measures will be individual, depending on its structure and operating modes. Acknowledgements The author thanks the employees of the Novosibirsk HPP and Vedeneev VNIIG JSC for assistance in performing the inspection and processing the results of the study. References Vasiliev, Yu., Petrenya, Yu., Georgievskaia, E., 2017. Lifetime of hydraulic turbines: Approaches, opinions, trends. The review of the Russian literature. Proceedings of the Russian Academy of Sciences. Energy 6, 59-73 (RU). Strelnikova, E., Syrota, I., Lynnyk, A., Kalema,t L., Zarhina, V., Zaydenvarg, O., 2017. Probabilistic estimation of the cracked shaft durability. Problems of mechanical engineering 20(1), 28-35 (RU). Dorji, U., Ghomashchi, R.,2014. Hydro turbine failure mechanisms: An overview. Engineering Failure Analysis 44, 136-147. Momčilović , D., Odanović , Z., Mitrović , R., Atanasovska, I., Vuherer, T., 2012. Failure analysis of hydraulic turbine shaft. Engineering failure analysis 20, 54-66. Makhutov, N., Petrenia, Y., Lepikhin, A., Moskvichev, V., Gadenin, M., Tchernyaev, A., 2020. Laboratory, Bench, and Full-Scale Researches of Strength, Reliability, and Safety of High-Power Hydro Turbines (Chapter 2). In Probability, Combinatorics and Control. InTech (Rijeka), London, pp. 322. Maricic, T., Haber, D., Pejovic, S., 2007. Standardization as prevention of fatigue cracking of hydraulic turbine-generator shaft, 2007 IEEE Canada Electrical Power Conference. Montreal, QC, Canada, pp. 103-110. Arsić, M., Bošnjak, S., Sedmak, S., Vistać, B., Savić, Z., 2019. Repair of cracks detected in cast components of vertical Kaplan turbine rotor hub. Structural Integrity and Life 19(3), 243-250. Sedmak, A., Bosnjak, S., Arsic, M., Sedmak, S. A., Savic, Z., 2016. Integrity and life estimation of turbine runner cover in a hydro power plant. Frattura ed Integrità Strutturale 10(36), 63-68. Neto, A. D. A., Gissoni, H., Gonçalves, M., Cardoso, R., Jung, A., Meneghini, J., 2016. Engineering diagnostics for vortex-induced stay vanes cracks in a Francis turbine. IOP Conference Series: Earth and Environmental Science 49(7), 072017. Aronson, A. Y., Zabelkin, V. M., Pylev, I. M., 1986. Causes of cracking in stay vanes of Francis turbines. Hydrotechnical Construction 20, 241 247. Georgievskaia, E., 2021. Destruction of the hydraulic unit shaft: Why it is possible? Forces in Mechanics 4, 100026. Georgievskaia E., Bashmakov A., Vasilchenko K., 2023. Fatigue cracks: Random or regularity. The Hydrotechnika 1(70), 2-9 (RU).