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Platero C.A.,Technical University of Madrid | Nicolet C.,Power Vision | Sanchez J.A.,Technical University of Madrid | Kawkabani B.,Ecole Polytechnique Federale de Lausanne
Renewable Energy | Year: 2014

The integration of wind power in power systems results in a reduction in greenhouse gas emissions. Thus, it has a positive environmental impact. However, the operation of these power systems becomes increasingly complex, owing mainly to random behaviour of the wind.In the case of island power systems, this problem is even more difficult. The traditional solution is to use diesel generators as an alternative power supply. For a wind-only power supply, an energy storage system is required. If the topography of the island makes possible the use of pumped storage hydropower plants, this is, nowadays, the most suitable energy storage system.This paper presents a novel method of Pelton turbine operation with no water flow, as a way to provide fast power injection in the case of an abrupt wind power decrease, or a wind-generator trip. This operation mode allows maximizing wind power penetration in a reliable and efficient way. This method has been validated by computer simulations, and will be tested during the commissioning of a combined wind-pumped storage power plant in an autonomous power system, on a small island. © 2014 Elsevier Ltd.

Ruchonnet N.,Ecole Polytechnique Federale de Lausanne | Alligne S.,Ecole Polytechnique Federale de Lausanne | Nicolet C.,Power Vision | Avellan F.,Ecole Polytechnique Federale de Lausanne
Journal of Fluids and Structures | Year: 2012

In pipe systems, pressure and flow fluctuations below cutoff frequency propagate as plane waves along pipes. Depending on the pipe length and propagation velocity, resonance leading to high amplitude pressure fluctuation may occur. At low pressure, cavitation is an important source of fluctuation. Beside its active role in the mechanism of noise generation, the cavitation reflects partially the incoming plane waves. This may modify the values of the eigenfrequencies of the system consisting of the pipe, the contained fluid and the vapor cavity. The influence of cavitation is experimentally investigated in a hydroacoustic resonator: a straight pipe connecting two tanks. At three quarters of the pipe length, a bluff body is placed cross flow to generate periodic vortex wake cavitation in a limited section of the pipe. The analysis of the wall pressure measurements along the hydroacoustic resonator results is performed with the help of a one-dimensional transient model of the pipe including the compliance of the cavities created in the wake of the bluff body. The results of the numerical simulations enable the determination of both the eigenvalues within the resulting system of equations and the mode shape of the pressure fluctuations corresponding to the experimental results. © 2011 Elsevier Ltd.

Padoan Jr. A.C.,Alstom | Kawkabani B.,Ecole Polytechnique Federale de Lausanne | Schwery A.,Alstom | Ramirez C.,Alstom | And 3 more authors.
IEEE Transactions on Power Systems | Year: 2010

The dynamic performances of variable speed and fixed speed units are compared in the case of 2 × 320 MW pumped storage power plant. The case study of the pumped storage power plant with standard synchronous machine with PSS is presented and, then, the corresponding variable speed system is designed for this case. Unsteady numerical simulations of both architectures enable to demonstrate that the variable speed architecture improves the power system stability characteristics for both the local and the inter-area modes of oscillation. Moreover, the damping of active power oscillations originated by the part load operation of the pump-turbine in generating mode is investigated as well. © 2010 IEEE.

Pannatier Y.,Ecole Polytechnique Federale de Lausanne | Kawkabani B.,Ecole Polytechnique Federale de Lausanne | Nicolet C.,Power Vision | Simond J.-J.,Ecole Polytechnique Federale de Lausanne | And 2 more authors.
IEEE Transactions on Industrial Electronics | Year: 2010

This paper presents the modeling, simulation, and analysis of the dynamic behavior of a fictitious 2 × 320 MW variable-speed pump-turbine power plant, including a hydraulic system, electrical equipment, rotating inertias, and control systems. The modeling of the hydraulic and electrical components of the power plant is presented. The dynamic performances of a control strategy in generating mode and one in pumping mode are investigated by the simulation of the complete models in the case of change of active power set points. Then, a pseudocontinuous model of the converters feeding the rotor circuits is described. Due to this simplification, the simulation time can be reduced drastically (approximately factor 60). A first validation of the simplified model of the converters is obtained by comparison of the simulated results coming from the simplified and complete models for different modes of operation of the power plant. Experimental results performed on a 2.2-kW low-power test bench are also compared with the simulated results coming from both complete and simplified models related to this case and confirm the validity of the proposed simplified approach for the converters. © 2006 IEEE.

Agency: Cordis | Branch: FP7 | Program: CP | Phase: ENERGY.2013.2.7.1 | Award Amount: 6.23M | Year: 2013

In the recent years due to tremendous development and integration of renewable energy resources in Europe, hydraulic turbines and pump-turbines are key technical components to contribute to renewable energy production and to compensate for the stochastic nature of the variable energy sources, preserving thus the electrical grid stability. As a result, the overarching objective of the project is the enhanced hydropower plant value by extending the flexibility of its operating range, while also improving its long-term availability. More specifically, the project aims to study the hydraulic, mechanical and electrical dynamics of several hydraulic machines configurations fresh and seawater turbines, reversible pump-turbines under an extended range of operations : from overload to deep part load. A two-pronged modelling approach will rely on numerical simulations as well as reduced-scale physical model tests. Upon suitable concurrence between simulations and reduced-scale physical models results, validation will take place on carefully selected physical hydropower plants properly equipped with monitoring systems. To address this ambitious research plan, a consortium has been assembled featuring three leading hydraulic turbines, storage pumps, reversible pump-turbine and electric equipment manufacturers, SME, as well as world-renowned academic institutions. Extensive tests both on both experimental rigs and real power plants will be performed in order to validate the obtained methodological and numerical results.

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