Scenarios for refurbishment of a hydropower plant equipped with Francis turbines

Muntean, Sebastian; Susan-Resiga, Romeo; Göde, E.; Baya, Alexandru; Terzi, Radu; Tîrşi, Constantin

doi:10.1051/rees/2016030

Cited by 7 publications

(4 citation statements)

References 13 publications

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“…For example, in the same way that Norway's hydropower provides much-needed flexibility to continental Europe's power system [23], there are several countries across Africa that could find themselves in comparable positions in a VRE-rich future, including Guinea in West Africa [11•, 18] and Ethiopia in East Africa [21•, 24, 25]. In this context, it is important to note that various older hydropower plants in Africa may need refurbishment to be able to provide better flexibility services to aid VRE integration in the future [26,27].…”

Section: Generation-driven Flexibilitymentioning

confidence: 99%

A Grid for all Seasons: Enhancing the Integration of Variable Solar and Wind Power in Electricity Systems Across Africa

Sterl

2021

Curr Sustainable Renewable Energy Rep

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Purpose of review This review paper assesses recent scientific findings around the integration of variable renewable electricity (VRE) sources, mostly solar PV and wind power, on power grids across Africa, in the context of expanding electricity access while ensuring low costs and reducing fossil fuel emissions. Recent findings In this context, significant research attention has been given to increased cross-border transmission infrastructure between African countries to harness the spatiotemporal complementarities between renewable electricity resources, as well as to storage options, such as battery storage and power-to-gas. Summary Much of the recent, model-based literature suggests that a combination of increased interconnections in and between Africa’s power pools, leveraging spatiotemporal complementarities between solar PV, wind and hydropower, as well as a large-scale deployment of storage options could help African countries meet their burgeoning power demand with largely decarbonized electricity supply.

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Section: Generation-driven Flexibilitymentioning

confidence: 99%

A Grid for all Seasons: Enhancing the Integration of Variable Solar and Wind Power in Electricity Systems Across Africa

Sterl

2021

Curr Sustainable Renewable Energy Rep

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“…Then, the helical flow pattern was described by the partial differential function (PDF) of the stream function. This PDF can be solved by converting it to constrained variational problems or under simplified conditions, and then validated by the finite-element method [29,30].…”

Section: Introductionmentioning

confidence: 99%

Analytical Implementation and Prediction of Hydraulic Characteristics for a Francis Turbine Runner Operated at BEP

et al. 2022

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The extensive investigation and profound understanding of the hydraulic characteristics of the Francis turbine are crucial to ensure a safe and stable hydraulic system. Especially, predicting the runner’s hydraulic efficiency with high fidelity is mandatory at the early stage of a new hydropower project. For these purposes, the current technologies mainly include experimentation and CFD simulation. Both methods generally have the demerits of a long period, massive investment and high requirements for supercomputers. In this work, an analytical solution is therefore introduced in order to predict the internal flow field and working performance of the runner while the Francis turbine operates at the best efficiency point (BEP). This approach, based on differential-geometry theory and the kinematics of ideal fluid, discretizes the blade channel by several spatial streamlines. Then, the dynamic parameters of these streamlines are determined in a curved-surface coordinate system, including velocity components, flow angles, Eulerian energy and pressure differences across the blade. Additionally, velocity components are converted from the spatial-velocity triangle to the Cartesian coordinate system, and the absolute-velocity vectors as well as the streamlines are subsequently derived. A validation of this approach is then presented. The analytical solution of hydraulic efficiency shows good agreement with the experimental value and simulation result. Additionally, the distributions of pressure differences over the blade, velocity and Eulerian energy are well predicted with respect to the CFD results. Finally, the discrepancy and distribution of the dynamic parameters are discussed.

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“…Nowadays hydropower is perceived as a mature technology but it has to face to new requirements more challenging than ever: the stochastic nature of renewable energy sources (wind, solar), irregular market requirements for energy, climate changes, constraints and environmental concerns [1]. Therefore, the hydraulic turbines have to operate over a wide range [2,3] under a fast change of the parameters to compensate the fluctuating part delivered in the electrical grid by the renewable energies. Several times, these requirements implied transient phenomena (e.g., load acceptance, load rejection, start-stop, emergency shutdown, spin no load, total load rejection) in operation [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

A Novel Passive Method to Control the Swirling Flow with Vortex Rope from the Conical Diffuser of Hydraulic Turbines with Fixed Blades

et al. 2019

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In this paper, we introduce a novel passive control method to mitigate the unsteadiness effects associated to the swirling flows with self-induced instabilities. The control method involves a progressive throttling cross-section flow at the outlet of the conical diffuser. It adjusts the cross-section area with a diaphragm while maintaining all positions of the circular shape centered on the axis. It improves the pressure recovery on the cone wall while the pressure fluctuations associated with the self-induced instability are mitigated as it adjusts the cross-section area. It can adjust the diaphragm in correlation with the operating conditions of the turbine. We investigated the passive control method on a swirl generator, which provides a similar flow as a hydraulic turbine operated at a partial discharge. The plunging and rotating components are discriminated using the pressure fluctuation on the cone wall to provide a clear view of the effects induced by this passive control method. As a result, the novel proof of concept examined in this paper offers valuable benefits as it fulfils a good balance between the dynamical behavior and the hydraulic losses.

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Scenarios for refurbishment of a hydropower plant equipped with Francis turbines

Cited by 7 publications

References 13 publications

A Grid for all Seasons: Enhancing the Integration of Variable Solar and Wind Power in Electricity Systems Across Africa

A Grid for all Seasons: Enhancing the Integration of Variable Solar and Wind Power in Electricity Systems Across Africa

Analytical Implementation and Prediction of Hydraulic Characteristics for a Francis Turbine Runner Operated at BEP

A Novel Passive Method to Control the Swirling Flow with Vortex Rope from the Conical Diffuser of Hydraulic Turbines with Fixed Blades

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