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dc.contributor.authorVagnoni, Elena
dc.contributor.authorValentín Ruiz, David
dc.contributor.authorAvellan, François
dc.contributor.otherUniversitat Politècnica de Catalunya. Departament de Mecànica de Fluids
dc.identifier.citationVagnoni, E.; Valentin, D.; Avellan, F. Dynamic behaviour of a Francis turbine during voltage regulation in the electrical power system. "International journal of electrical power and energy systems", 1 Febrer 2021, vol. 125, núm. 106474, p. 106419:1-106419:10.
dc.description.abstractHydroelectric units can be operated in synchronous condenser mode to provide reactive power to the electrical power system (EPS) for voltage regulation. In this operating mode, the hydraulic turbine consumes active power and in case of hydroelectric units equipped with a Francis turbine, pressurized air is injected in the draft tube to decrease the tailwater level below the runner for decreasing the friction losses. Several dynamic phenomena have been recorded during full-scale hydraulic turbine operation due to the air–water mixing causing pressure and torque fluctuations which may compromise the operation and safety of both the hydraulic machine and the EPS. In this paper, the study of the dynamic response of a Francis turbine prototype during synchronous condenser mode operation is performed to evaluate the transposition of the machine behaviour from the homologous reduced scale model to the full-scale prototype. Measurements of the pressure in draft tube cone, machine vibrations, and torque are performed in both full scale prototype and reduced scale model. The analysis of the dynamic behaviour of the hydraulic turbine focuses on the critical vibrations and power fluctuations. The onset of a sloshing wave in the draft tube cone is highlighted as predicted by the reduced scale model tests. Rotor–stator interactions (RSI) are analyzed and compared to the RSI during generating mode operation. The advantages of decreasing the pressure in the vaneless gap between the runner blades and the closed guide vanes by installing a draining pipe are emphasized to limit the amplitude of the fluctuations and to avoid unwanted two-phase flow phenomena in the vaneless gap which can perturb the machine operation and safety.
dc.rightsAttribution-NonCommercial-NoDerivs 3.0 Spain
dc.subjectÀrees temàtiques de la UPC::Enginyeria mecànica
dc.subjectÀrees temàtiques de la UPC::Energies
dc.subjectÀrees temàtiques de la UPC::Energies::Energia hidràulica
dc.subject.lcshHydraulic turbines
dc.subject.lcshHydroelectric power-plants
dc.subject.lcshHydraulic motors
dc.subject.otherHydro unit commitment
dc.subject.otherShort-term hydropower optimization
dc.subject.otherMixed integer linear programming
dc.titleDynamic behaviour of a Francis turbine during voltage regulation in the electrical power system
dc.subject.lemacTurbines hidràuliques
dc.subject.lemacCentrals hidroelèctriques
dc.subject.lemacMotors hidràulics
dc.contributor.groupUniversitat Politècnica de Catalunya. FLUIDS - Enginyeria de Fluids
dc.rights.accessOpen Access
dc.description.versionPostprint (published version)
local.citation.authorVagnoni, E.; Valentin, D.; Avellan, F.
local.citation.publicationNameInternational journal of electrical power and energy systems

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Except where otherwise noted, content on this work is licensed under a Creative Commons license : Attribution-NonCommercial-NoDerivs 3.0 Spain