Feasibility of Detecting Natural Frequencies of Hydraulic Turbines While in Operation, Using Strain Gauges

Nowadays, hydropower plays an essential role in the energy market. Due to their fast response and regulation capacity, hydraulic turbines operate at off-design conditions with a high number of starts and stops. In this situation, dynamic loads and stresses over the structure are high, registering so...

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Main Authors: David Valentín, Alexandre Presas, Matias Bossio, Mònica Egusquiza, Eduard Egusquiza, Carme Valero
Format: Article
Language:English
Published: MDPI AG 2018-01-01
Series:Sensors
Subjects:
Online Access:http://www.mdpi.com/1424-8220/18/1/174
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author David Valentín
Alexandre Presas
Matias Bossio
Mònica Egusquiza
Eduard Egusquiza
Carme Valero
author_facet David Valentín
Alexandre Presas
Matias Bossio
Mònica Egusquiza
Eduard Egusquiza
Carme Valero
author_sort David Valentín
collection DOAJ
description Nowadays, hydropower plays an essential role in the energy market. Due to their fast response and regulation capacity, hydraulic turbines operate at off-design conditions with a high number of starts and stops. In this situation, dynamic loads and stresses over the structure are high, registering some failures over time, especially in the runner. Therefore, it is important to know the dynamic response of the runner while in operation, i.e., the natural frequencies, damping and mode shapes, in order to avoid resonance and fatigue problems. Detecting the natural frequencies of hydraulic turbine runners while in operation is challenging, because they are inaccessible structures strongly affected by their confinement in water. Strain gauges are used to measure the stresses of hydraulic turbine runners in operation during commissioning. However, in this paper, the feasibility of using them to detect the natural frequencies of hydraulic turbines runners while in operation is studied. For this purpose, a large Francis turbine runner (444 MW) was instrumented with several strain gauges at different positions. First, a complete experimental strain modal testing (SMT) of the runner in air was performed using the strain gauges and accelerometers. Then, the natural frequencies of the runner were estimated during operation by means of analyzing accurately transient events or rough operating conditions.
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spelling doaj.art-de5de054fc7b42dc9aa3841bfdab57492022-12-22T04:25:17ZengMDPI AGSensors1424-82202018-01-0118117410.3390/s18010174s18010174Feasibility of Detecting Natural Frequencies of Hydraulic Turbines While in Operation, Using Strain GaugesDavid Valentín0Alexandre Presas1Matias Bossio2Mònica Egusquiza3Eduard Egusquiza4Carme Valero5Center for Industrial Diagnostics and Fluid Dynamics (CDIF), Polytechnic University of Catalonia (UPC), Av. Diagonal, 647, ETSEIB, 08028 Barcelona, SpainCenter for Industrial Diagnostics and Fluid Dynamics (CDIF), Polytechnic University of Catalonia (UPC), Av. Diagonal, 647, ETSEIB, 08028 Barcelona, SpainCenter for Industrial Diagnostics and Fluid Dynamics (CDIF), Polytechnic University of Catalonia (UPC), Av. Diagonal, 647, ETSEIB, 08028 Barcelona, SpainCenter for Industrial Diagnostics and Fluid Dynamics (CDIF), Polytechnic University of Catalonia (UPC), Av. Diagonal, 647, ETSEIB, 08028 Barcelona, SpainCenter for Industrial Diagnostics and Fluid Dynamics (CDIF), Polytechnic University of Catalonia (UPC), Av. Diagonal, 647, ETSEIB, 08028 Barcelona, SpainCenter for Industrial Diagnostics and Fluid Dynamics (CDIF), Polytechnic University of Catalonia (UPC), Av. Diagonal, 647, ETSEIB, 08028 Barcelona, SpainNowadays, hydropower plays an essential role in the energy market. Due to their fast response and regulation capacity, hydraulic turbines operate at off-design conditions with a high number of starts and stops. In this situation, dynamic loads and stresses over the structure are high, registering some failures over time, especially in the runner. Therefore, it is important to know the dynamic response of the runner while in operation, i.e., the natural frequencies, damping and mode shapes, in order to avoid resonance and fatigue problems. Detecting the natural frequencies of hydraulic turbine runners while in operation is challenging, because they are inaccessible structures strongly affected by their confinement in water. Strain gauges are used to measure the stresses of hydraulic turbine runners in operation during commissioning. However, in this paper, the feasibility of using them to detect the natural frequencies of hydraulic turbines runners while in operation is studied. For this purpose, a large Francis turbine runner (444 MW) was instrumented with several strain gauges at different positions. First, a complete experimental strain modal testing (SMT) of the runner in air was performed using the strain gauges and accelerometers. Then, the natural frequencies of the runner were estimated during operation by means of analyzing accurately transient events or rough operating conditions.http://www.mdpi.com/1424-8220/18/1/174natural frequencieshydraulic turbinestrain gaugesmodal analysis
spellingShingle David Valentín
Alexandre Presas
Matias Bossio
Mònica Egusquiza
Eduard Egusquiza
Carme Valero
Feasibility of Detecting Natural Frequencies of Hydraulic Turbines While in Operation, Using Strain Gauges
Sensors
natural frequencies
hydraulic turbine
strain gauges
modal analysis
title Feasibility of Detecting Natural Frequencies of Hydraulic Turbines While in Operation, Using Strain Gauges
title_full Feasibility of Detecting Natural Frequencies of Hydraulic Turbines While in Operation, Using Strain Gauges
title_fullStr Feasibility of Detecting Natural Frequencies of Hydraulic Turbines While in Operation, Using Strain Gauges
title_full_unstemmed Feasibility of Detecting Natural Frequencies of Hydraulic Turbines While in Operation, Using Strain Gauges
title_short Feasibility of Detecting Natural Frequencies of Hydraulic Turbines While in Operation, Using Strain Gauges
title_sort feasibility of detecting natural frequencies of hydraulic turbines while in operation using strain gauges
topic natural frequencies
hydraulic turbine
strain gauges
modal analysis
url http://www.mdpi.com/1424-8220/18/1/174
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