Discharge measurement in low head hydro power plants

摘要

Methods for discharge measurements in low head hydro power plants are presented with a series of field studies. The most classical method is the multipoint velocity measurement with propeller type current meters. For discharge evaluation, the integration of the difference between measured velocities and a known velocity distribution is recommended, thus avoiding integration in the outer zones with exponential velocity decay. The newest and best suited method for measurements in intakes is the acoustic scintillation method, a cross-correlation method. For accurate results the scintillation method must be installed downstream of trash racks. The method of acoustic transit measurement can also be adopted to measurements in low head, but new procedures for weighting the individual path velocities have to be applied due to varying shape of the flow cross sections.