Publications by Elena Vagnoni | EPFL Graph Search

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Hydraulic turbines and pump-turbines are often required to operate in particular conditions at which they consume active power. To keep the power consumption at a minimum, it is necessary to dewater the runner to reduce the mechanical torque. One of these ...

The most exploited renewable energy at a global scale is hydropower, which nowadays accounts for the 18 % of the world’s electricity supply. Its production is expected to increase approximately 3.1% each year in the next 25 years maintaining its share in t ...

With a continuously growing share of non-dispatchable renewable energy sources in the power mix, flexibility in hydropower provision is becoming fundamental. The major role played by hydropower in frequency regulation in the last years has underlined the p ...

All rights reserved.In recent decades, the electricity industry has undergone a significant transformation from a vertically integrated supply system to a market-regulated structure. This shift, along with the intermittent nature of increasingly prevalent ...

About 50% of all hydropower plants (HPPs) worldwide were originally commissioned more than 40 years ago, so that the advanced age of the fleet is a major concern across all continents, and especially in Europe. The modernization of HPPs can generate severa ...

This paper proposes a methodology to optimize the dispatch and reserve between multiple units in a Hydroelectric Power Plant (HPP) that makes use of the Hydraulic Short Circuit (HSC) operating mode. HSC allows for the simultaneous generation and pumping fr ...

Hydropower units may be required to operate in condenser mode to supply reactive power. In this operating mode, the water level in the turbine or pump-turbine is decreased below the runner by closing the guide vanes and injecting pressurized air. While ope ...

Hydroelectric 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 ...

This paper presents a solution to address wear and tear of Run-of-River (RoR) Hydropower Plants (HPPs) providing enhanced Frequency Containment Reserve (FCR). In this respect, the study proposes the integration of a Battery Energy Storage System (BESS) wit ...

Francis turbines with medium or high specific speeds may experience a particular type of instability in the upper part load in which the precessing vortex has an elliptical shape. The occurrence of the upper part-load instability (UPLI) is accompanied by l ...

The hydropower sector has recently raised the interest in pump as turbine (PaT) that can be a valid trade-off between capital cost and performance in micro-scale installations. Nevertheless, the modest efficiency of PaTs often restricts their exploitation. ...

Francis turbines operating in full load conditions feature an axisymmetric vortex rotating in the opposite direction of the turbine runner. In low-pressure conditions, the resulting cavitation vortex may enter in an unstable self-exciting process, leading ...

This paper proposes and experimentally validates a joint control and scheduling framework for a grid-forming converter-interfaced Battery Energy Storage Systems (BESSs) providing multiple services to the electrical grid. The framework is designed to dispat ...

This study explores the practical viability of repurposing aging Kaplan turbines into variable-speed propellers by employing full-size frequency converters. The motivation behind this approach is to improve the provision of Frequency Containment Reserve (F ...

The European Green Deal is prescribing a very ambitious rise in the annual production of renewable energy sources, and grid regulation services are increasingly important in the course of a massive integration of intermittent renewable energy sources. Alth ...

Hydropower has played an important role in Europe in recent decades, offering a unique combination of safe, low-cost, and clean power generation. Today, it is still one of the largest renewable energy sources (RES), accounting for about 35 % of RES electri ...

The progressive displacing of conventional generation in favor of renewable energy sources requires restoring an adequate capacity of regulating power to ensure reliable operation of power systems. Battery Energy Storage Systems (BESSs) are considered to b ...

This paper presents preliminary results of an experimental study on the occurrence and development of the upper part-load instability in a reduced-scale Francis turbine. The study includes draft tube pressure measurements, high-speed flow visualization, an ...

Achieving accurate predictions of transient processes for pumped-storage hydropower stations (PSHSs) remains a key challenge due to uncertainties in on-site parameters, particularly the pump-turbine characteristic curves (PTCCs), and limitations of the phy ...

The paper presents a model-based control strategy for optimal asset management of hydroelectric units in run-of-river hydropower plants. The proposed control strategy aims to operate the unit at the best efficiency while improving water flow management and ...

Elena Vagnoni

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Two-phase flow phenomena in hydraulic turbines and pump-turbines operating in synchronous condenser mode

Experimental evaluation of the velocity profiles and performance of a counter rotating micro-turbine by 2D laser Doppler velocimetry

Experimental facility for reduced scale model testing of hydraulic machines hybridized with a battery energy storage system

Evaluation of the fatigue-related influence of start-ups on Pelton turbines based on reduced scale model stress measurements

Assessing the energy potential of modernizing the European hydropower fleet

Optimal Short-Term Dispatch of Pumped-Storage Hydropower Plants Including Hydraulic Short Circuit

Experimental investigation of the sloshing motion of the water free surface in the draft tube of a Francis turbine operating in synchronous condenser mode

Dynamic behaviour of a Francis turbine during voltage regulation in the electrical power system

Enhanced Frequency Containment Reserve provision from battery hybridized hydropower plants: Theory and experimental validation

Upper part-load instability in a reduced-scale Francis turbine: an experimental study

Numerical investigation on the volute cutwater for pumps running in turbine mode

Prediction of unstable full load conditions in a Francis turbine prototype

Optimal grid-forming control of battery energy storage systems providing multiple services: Modeling and experimental validation

Experimental investigation of repurposed Kaplan turbines as variable-speed propellers for maximizing Frequency Containment Reserve

On the modelling of the fatigue-induced damage in Francis turbines start-up sequences

The new role of sustainable hydropower in flexible energy systems and its technical evolution through innovation and digitalization

Local Effects of Grid-Forming Converters Providing Frequency Regulation to Bulk Power Grids

An experimental study on the upper part-load elliptical vortex instability in a Francis turbine

A physics-based and data-aided transient prediction framework for sustainable operation of pumped-storage hydropower systems

Improving frequency containment reserve provision in run-of-river hydropower plants