Comparing acoustic scintillation and current meters discharge measurements at a mid-head HPP

International audienceThis paper presents results obtained by EDF and WEST S.r.l. made a joint efficiency measurement test on a HPP in the South East of France, for the commissioning of a major 120 MW Francis turbine. Two absolute methods were implemented on this site: on one hand, current meters (CM), performed by WEST Company, as the code-approved method to be used to check the guarantees. On the other hand, the acoustic scintillation flow meter (ASFM) was implemented by EDF in the intake simultaneously. A large number of current meters (90) for this kind of operation were used, installed on a stationary frame made up of 9 hydraulically-profiled beams. Acoustic scintillation transducers were installed on steel plates mounted directly on the intake wall. Flow conditions were quite good for both methods. The entire efficiency/power range of the turbine was explored using both methods giving absolute discharge measurements. The benefit of using new algorithms derived from a previous PhD 1 work sponsored by EDF, even in these quite good conditions, will also be emphasized. A fairly good level of agreement was achieved between both absolute methods; the agreement was slightly improved when applying the new " SMASH " algorithms. The average difference between CM and ASFM discharge values lies beneath the combined uncertainties of the two methods