Application of LISST instrument for suspended sediment and erosive wear prediction in run-of-river hydropower plants

摘要

In run-of-river or diversion type hydropower projects, a small reservoir is created by constructing an intake weir to divert river flow through head race tunnel to an adjacent valley utilizing the available head for power generation. The projects are also developed based on the concept of sustaining reservoir life by sediment management achieved by a desilting basin. Sediment can damage turbines and other mechanical equipment through erosion of the coating on the blades, leading to surface irregularities and more serious material damage. In this study, the suspended sediment concentrations and the particle size distribution at the intake weir and the settling basin of a run-of-river hydropower plant in Bentong Malaysia were measured using Laser In-Situ Scattering and Transmissometry (LISST) instrument. The measurements were performed in vertical line at four different depths around the intake and the mean particle size distribution was calculated from the data for each measured point. The measurements in the intake were particularly interesting since the concentration and the sizes of the particles, which will likewise to further enter the head race tunnel could be evaluated. Considering uncertainties of sediments estimation due to the hydrological and meteorological variability, Pearson system was used to estimate the erosion wear on the turbine based on the measured data.