Turbine mode start-up simulation of a FSFC variable speed pump-turbine prototype – Part I: 1D simulation

Abstract Variable speed hydroelectric units equipped with full size frequency converter (FSFC) offer high operational flexibility enabling fast operating point transitions which increase grid regulation capacities. The XFLEX HYDRO H2020 European research project aims to demonstrate of such technology at prototype scale. Z’Mutt pumping station, part the Grande Dixence scheme located in Switzerland, is one demonstrators focused on FSFC a new 5 MW reversible Francis pump-turbine will be commissioned 2021. This paper, divided two parts, simulate turbine mode start-up sequence made possible use and assess unit damage by means 1D 3D CFD simulations. I this paper presents hydraulic transient simulation results sequences U5 considering both conventional fixed variable technology. time evolution unit’s used as input data for simulations II, aiming impeller damage. Different control strategies are analysed. Advantages limits each strategy discussed, recommendation demonstrator.