Experimental and numerical investigations of a high-head pumped-storage power plant at speed no-load.

29th IAHR Symposium on Hydraulic Machinery and Systems

Decaix, J.^1 ; Hasmatuchi, V.^1 ; Titzschkau, M.^2 ; Rapillard, L.^1 ; Manso, P.^3 ; Avellan, F.^4 ; Münch-Alligné, C.^1

University of Applied Sciences and Arts Western Switzerland Valais, Route du Rawil 47, Sion

CH-1950, Switzerland^1

Kraftwerke Oberhasli AG (KWO), Grimsel Hydro, Innertkirchen, Switzerland^2

Ecole Polytechnique Fédérale de Lausanne (EPFL), Plateforme de Constructions Hydrauliques (PL-LCH), Lausanne

CH-1015, Switzerland^3

Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratoire de Machines Hydrauliques (LMH), Lausanne, CH-1007, Switzerland^4

关键词: Flow instabilities;    Frequency spectra;    Mechanical stress;    Numerical investigations;    On-board measurements;    Operating condition;    Pumped storage plants;    Renewable energies;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/240/8/082014/pdf
DOI  :  10.1088/1755-1315/240/8/082014

来源: IOP

【 摘 要 】

Due to the increasing integration of new renewable energies, the electrical grid undergoes more frequent instabilities. Hydroelectric power plants, particularly pumped storage plants, are well suited for grid control. However, this objective requires extending the operating range of the machines and increasing the number of start-up, stand-by and shut-down procedures, which reduces the lifespan of the machines due to high mechanical stresses. The current study focuses on a pumped-storage power plant equipped with ternary groups. Recently, cracks on the runner blades of the Francis turbine have been observed without finding a clear explanation for their onset. During this period, the number of starts and stops per day has strongly increased. In order to better understand the origin of the fatigue of the turbine runner, external and on-board measurements along with CFD and FEM investigations have been performed. The on-board measurements provide evidence high mechanical stresses on the runner blades during the synchronization of the machine at speed no-load (SNL) operating condition. The frequency spectrum observed on the various signals suggests that the high stresses are linked to the excitation of one of the runner modes by some flow instabilities, which is supported by the CFD and FEM analyses.