Search results for "hydropower"
showing 10 items of 30 documents
RECUPERO ENERGETICO ALL’INTERNO DELLE RETI ACQUEDOTTISTICHE MEDIANTE MICROTURBINE IDRAULICHE
2022
Impact of micro hydropower (MHP) based electrification on rural livelihoods : case study Nam Mong in Luang Prabang province, Lao PDR
2009
Axial Flux Permanent Magnet Synchronous Generators for Pico Hydropower Application: A Parametrical Study
2022
A pico hydropower plant is an energy harvesting system that allows energy production using the power of the water flowing in small watercourses, and in water distribution network. Axial Flow Flux Permanent Magnet Synchronous Generator (AFPMSG) are particularly suitable for this application, being efficient machines that achieve high power with small dimensions. This paper presents a parametrical study of several configurations and topologies of three-phase and single-phase AFPMSG, for pico hydropower application, to assess the most suitable dimensional characteristics for the most energy production using a safe voltage of 25 V. The AFPMSGs here considered has a simple single stator and roto…
Coupled Electric and Hydraulic Control of a PRS Turbine in a Real Transport Water Network
2019
Although many devices have recently been proposed for pressure regulation and energy harvesting in water distribution and transport networks, very few applications are still documented in the scientific literature. A new in-line Banki turbine with positive outflow pressure and a mobile regulating flap, named Power Recovery System (PRS), was installed and tested in a real water transport network for the regulation of pressure and flow rate. The PRS turbine was directly connected to a 55 kW asynchronous generator with variable rotational velocity, and coupled to an inverter. The start-up tests showed how automatic adjustment of the flap position and the runner velocity variation are able to c…
Rehabilitation of two northern river lamprey (Lampetra fluviatilis) populations impacted by various anthropogenic pressures : lessons learnt in the p…
2019
The pioneering work done during the past three decades in the regulated Rivers Perhonjoki and Kalajoki, Finland, to study and rehabilitate river lamprey populations is presented. The effects of various anthropogenic activities and rehabilitation measures are evaluated based on habitat surveys and long-term monitoring of larval densities, numbers of adults migrating upstream and of transformers migrating downstream. Telemetric tracking and tagging experiments were used to determine the efficacy of fishways. Lamprey populations in both rivers decreased in the 1980s and 1990s. This was linked to obstructed upstream migration of adults and deterioration of habitats for different life stages due…
Analytical-numerical analysis of closed-form dynamic model of Sayano-Shushenskaya hydropower plant : stability, oscillations, and accident
2021
This work is devoted to the analysis of a mathematical model of hydropower unit, consisting of synchronous generator, hydraulic turbine, and speed governor. It is motivated by the accident happened on the Sayano-Shushenskaya hydropower plant in 2009 year. In the analysis we follow the line of classical control theory approach developed in the works of famous scientists J.C. Maxwell, I.A. Vishnegradsky, A.A. Andronov, and F. Tricomi for the study of centrifugal turbine governor and electrical machines limit-load problem. It is shown that the occurrence of vibrations in the Sayano-Shushenskaya hydropower plant can be caused by nonlinear dynamics of the closed-form model. peerReviewed
DEVIATORE DI FLUSSO PER TURBINE IDRAULICHE IN LINEA
2021
Un deviatore di flusso per una turbina idraulica a flusso incrociato presenta una sezione di uscita atta ad essere collegata alla sezione a valle della condotta idraulica per l’immissione di un flusso in uscita del fluido liquido in pressione con un vettore di velocità di uscita avente modulo di uscita (Vo) e direzione di uscita (do) predeterminati, un condotto di scarico per il ripristino del vettore velocità di detto flusso in uscita al modulo in ingresso ed a una direzione di uscita sostanzialmente parallela o coincidente con detta direzione di ingresso (di), in cui detto deviatore comprende, un primo settore immediatamente a valle di detta girante ed atto a variare la direzione del flus…
A New Cross-Flow Type Turbine for Ultra-Low Head in Streams and Channels
2023
In the last few decades, hydropower production has been moving toward a new paradigm of low and diffused power density production of energy with small and mini-hydro plants, which usually do not require significant water storage. In the case of nominal power lower than 20 kW and ultra-low head H (H < 5 m), Archimedes screw or Kaplan type turbines are usually chosen due to their efficiency, which is higher than 0.85. A new cross-flow type turbine called Ultra-low Power Recovery System (UL-PRS) is proposed and its geometry and design criteria are validated in a wide range of operating conditions through 2D numerical analysis computed using the ANSYS Fluent solver. The new proposed solution…
Performance Improvement of a Drag Hydrokinetic Turbine
2021
Hydropower is at present in many locations, among all the other possible renewable energy sources, the best one for net cost per unit power. In contrast to traditional installation, based on water storage in artificial basins, free flow river turbines also provide a very low environmental impact due to their negligible effect on solid transport. Among them, kinetic turbines with vertical axis are very inexpensive and have almost zero impact on fish and local fauna. In application to tidal waves and sea waves, where vertically averaged velocities have alternate direction, a Savonius rotor also has the advantage of being productive during the whole time cycle. In this work, the effect of an u…
Impacts of reduced Lepidurus arcticus availability on brown trout life history traits in a mountain reservoir
2020
Lepidurus arcticus (the Arctic tadpole shrimp) is a vulnerable keystone species in Arctic and alpine water bodies where its occurrence and population size may influence the viability and life history traits of resident salmonids. Using data from a Norwegian mountain hydropower reservoir, Aursjoen, we illustrate how reduced availability of L. arcticus as prey resulted in the reduced condition, growth and delayed maturation of resident brown trout (Salmo trutta). We further link changes in the relative abundance of L. arcticus as prey to changing reservoir conditions, e.g. water level changes in the spring period, thereby establishing an indirect link between reservoir operation regimes and b…