2024
Wang, Wenjie; Qiu, Gai; Pei, Ji; Pavesi, Giorgio; Tai, Geyuan; Yuan, Shouqi
Effect of return channel on performance and pressure fluctuation of pump turbine Journal Article
In: Physics of Fluids, vol. 36, iss. 10, 2024, ISSN: 10897666.
Abstract | Links | BibTeX | Tags: Closure of Wicket Gate, Guide Vane Closure, Hydro plant control, Pumped hydro storage
@article{Wang2024,
title = {Effect of return channel on performance and pressure fluctuation of pump turbine},
author = {Wenjie Wang and Gai Qiu and Ji Pei and Giorgio Pavesi and Geyuan Tai and Shouqi Yuan},
doi = {10.1063/5.0229130},
issn = {10897666},
year = {2024},
date = {2024-01-01},
urldate = {2024-01-01},
journal = {Physics of Fluids},
volume = {36},
issue = {10},
publisher = {American Institute of Physics},
abstract = {To stabilize the operation of pumped storage power station, an orthogonal experimental design was proposed to optimize the return channel with the splitter blades of the pump turbine. The calculation results of various return channel models under multiple operating conditions indicated that inlet distance a1 and blade number z considerably affect the efficiency and flow pattern in the flow passage. The optimal scheme improved efficiency by nearly 3% at 0.6Qd. The Savitzky-Golay filtering method and Fast Fourier Transform were used to analyze the unsteady characteristics of the pump turbine in pump model. The amplitude of pressure pulsations at the blade passing frequency in the vaneless space and the interference zone between the guide vane and return channel reduced considerably, and the pressure pulsation amplitude in the vaneless zone decreased by 50%, 48%, and 20% for 0.6Qd, 1.0Qd, and 1.1Qd operating conditions. A Continuous Wavelet Transform was used to analyze frequency signals during the shutdown transition process. The optimization of the splitter blades improved the flow pattern in their corresponding flow passages and suppressed high-amplitude pressure pulsations in the unit for the stable operation of the pumped storage power station.},
keywords = {Closure of Wicket Gate, Guide Vane Closure, Hydro plant control, Pumped hydro storage},
pubstate = {published},
tppubtype = {article}
}
To stabilize the operation of pumped storage power station, an orthogonal experimental design was proposed to optimize the return channel with the splitter blades of the pump turbine. The calculation results of various return channel models under multiple operating conditions indicated that inlet distance a1 and blade number z considerably affect the efficiency and flow pattern in the flow passage. The optimal scheme improved efficiency by nearly 3% at 0.6Qd. The Savitzky-Golay filtering method and Fast Fourier Transform were used to analyze the unsteady characteristics of the pump turbine in pump model. The amplitude of pressure pulsations at the blade passing frequency in the vaneless space and the interference zone between the guide vane and return channel reduced considerably, and the pressure pulsation amplitude in the vaneless zone decreased by 50%, 48%, and 20% for 0.6Qd, 1.0Qd, and 1.1Qd operating conditions. A Continuous Wavelet Transform was used to analyze frequency signals during the shutdown transition process. The optimization of the splitter blades improved the flow pattern in their corresponding flow passages and suppressed high-amplitude pressure pulsations in the unit for the stable operation of the pumped storage power station.
2016
Pavesi, Giorgio; Cavazzini, Giovanna; Ardizzon, Guido
Numerical analysis of the transient behaviour of a variable speed pump-turbine during a pumping power reduction scenario Journal Article
In: Energies, vol. 9, iss. 7, pp. 1-15, 2016, ISSN: 19961073.
Abstract | Links | BibTeX | Tags: Adjustable Speed Hydro Plants, Dynamic response, Dynamic response of hydro plants, Hydro plant control, Pump as Turbine, Variable Speed, Variable-speed regulation
@article{pop00005,
title = {Numerical analysis of the transient behaviour of a variable speed pump-turbine during a pumping power reduction scenario},
author = {Giorgio Pavesi and Giovanna Cavazzini and Guido Ardizzon},
url = {http://www.mdpi.com/1996-1073/9/7/534 http://www.mdpi.com/1996-1073/9/7/534/htm},
doi = {10.3390/en9070534},
issn = {19961073},
year = {2016},
date = {2016-01-01},
urldate = {2016-01-01},
journal = {Energies},
volume = {9},
issue = {7},
pages = {1-15},
publisher = {mdpi.com},
abstract = {To achieve the carbon free electricity generation target for 2050, the penetration of renewable energy sources should further increase. To address the impacts of their unpredictable and intermittent characteristics on the future electricity grid, Pumped Hydro Energy Storage (PHES) plants should enhance their regulation capability by extending their continuous operating range far beyond the optimal normal working range. However, for the time being, the regulation capability of the new generation of PHES, equipped with reversible pump-turbines due to their cost-effectiveness, is limited at part load by instability problems. The aim of this paper is to analyse, during a pumping power reduction scenario, the onset and development of unsteady phenomena leading to unstable behaviour. A 3D transient numerical simulation was carried out on the first stage of a variable-speed two-stage pump-turbine from full load to the unstable operating zone by progressively reducing the speed from 100% to 88% rpm corresponding to a power reduction from full load to about 60% with a ramp rate of 1.5% per s. Two three-dimensional unsteady flow structures affecting the return channel and the wicket gates at the end of the first stage were identified and their evolution in the power regulation scenario was fluid-dynamically and spectrally characterized to determine the fluid-dynamical conditions causing the head drop in the hump zone.},
keywords = {Adjustable Speed Hydro Plants, Dynamic response, Dynamic response of hydro plants, Hydro plant control, Pump as Turbine, Variable Speed, Variable-speed regulation},
pubstate = {published},
tppubtype = {article}
}
To achieve the carbon free electricity generation target for 2050, the penetration of renewable energy sources should further increase. To address the impacts of their unpredictable and intermittent characteristics on the future electricity grid, Pumped Hydro Energy Storage (PHES) plants should enhance their regulation capability by extending their continuous operating range far beyond the optimal normal working range. However, for the time being, the regulation capability of the new generation of PHES, equipped with reversible pump-turbines due to their cost-effectiveness, is limited at part load by instability problems. The aim of this paper is to analyse, during a pumping power reduction scenario, the onset and development of unsteady phenomena leading to unstable behaviour. A 3D transient numerical simulation was carried out on the first stage of a variable-speed two-stage pump-turbine from full load to the unstable operating zone by progressively reducing the speed from 100% to 88% rpm corresponding to a power reduction from full load to about 60% with a ramp rate of 1.5% per s. Two three-dimensional unsteady flow structures affecting the return channel and the wicket gates at the end of the first stage were identified and their evolution in the power regulation scenario was fluid-dynamically and spectrally characterized to determine the fluid-dynamical conditions causing the head drop in the hump zone.
