Author(s): C. Badina (Neagoie); P. Bryla; E. Millon

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Keywords: Dynamic pressure fluctuations; Penstock liner; Hydraulic transients; Strain gauges; Spectral analysis

Abstract: In the beginning, a presentation of the international TS63111 Technical Specification on hydraulic transient phenomena of hydro turbines, storage pumps and pump-turbines will be done. The Specification has been submitted for comments to the IEC TC4 Countries Committees and it deals with the factors that affect the hydraulic transients, the recommend modelling, design, and the best practice for site measurement and guarantee evaluation. With respect to the pressure measurement during transient testing and the calibration of the transient modeling following the site measurement, sometimes the dynamic pressure fluctuations are not considered and only the average value is indicated. During the testing, a full attention should be given not only to the measurements conditions but also to the equipment used and not least the sampling rate used for the acquisition. The paper presents the findings of EDF-DTG during the testing performed in some power plants and the mechanical impact of high frequency pressure fluctuations on the penstock liner. During the testing, the penstock has been equipped with classic pressure transducers and with strain gauges in order to demonstrate that the high frequency pressure fluctuations have also a mechanical impact on the liner and should be considered in the evaluation of the guarantee. A comparison between the stress calculated as an effect of the pressure and the stress given by the strain gauges have been performed on the signals together with the classical Spectral analysis.

DOI: https://doi.org/10.1088/1755-1315/1483/1/012033

Year: 2023