Dealing with Pelton turbine erosion based on systematic monitoring

Hydro-abrasive erosion in hydraulic turbines is a weil known problem, but comprehensive data sets from hydropower plants are still rare. Therefore, the sediment load, erosion depths and efficiency changes have been measured and evaluated since 2012 at a high-head run-of-river hydro plant in the Swiss Alps. An erosion model for hard-coated Pelton buckets was calibrated based on the data obtained. lt is demonstrated that hydro plant shutdowns in periods of exceptionally high erosion potential are profitable. A procedure to estimate a site-specific threshold value of suspended sediment concentration for hydro plant shutdowns is proposed.