Performance Optimization of Hydraulic Turbine by Use of Variable Rotating Speed

Abubakirov, Sh. I.; Lunatsi, M. E.; Plotnikova, T. V.; Sokur, P. V.; Tuzov, P. Yu.; Shavarin, V. N.; Shakaryan, Yu. G.; Shchur, Vsevolod

doi:10.1007/s10749-013-0405-6

Cited by 9 publications

(2 citation statements)

References 1 publication

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“…Owning to the pioneering work done in Japan on variable speed operation (VSO) of reversible pump-turbines [9][10][11][12], several researchers have explored the idea to apply this technology to improve off-design efficiency of conventional Francis turbines [13][14][15]. However, both old and recent studies have shown that for low specific speed Francis turbines operated close to their rated head, such as most of the installed turbines in Norway are, enabling VSO might result in minor efficiency improvements [13,16,17].…”

Section: Introductionmentioning

confidence: 99%

Optimization of Francis Turbines for Variable Speed Operation Using Surrogate Modeling Approach

Iliev

Tengs²,

Trivedi³

et al. 2020

Journal of Fluids Engineering

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Previous studies suggested variable speed operation of Francis turbines as a measure to improve the efficiency at off-design operating conditions. This is, however, strongly dependent on the hydraulic design and, for an existing turbine, improvements can be expected only with a proper redesign of the hydraulic surfaces. Therefore, an optimization algorithm is proposed and applied to the runner of a low specific speed Francis turbine, with an optimization strategy specifically constructed to improve the variable speed performance. In the constrained design space of the reference turbine, the geometry of the replacement runner is parametrically defined using 15 parameters. Box-Behnken method was used to populate the design space with 421 unique samples, needed to train fully quadratic response surface models of three characteristic efficiencies defined by the proposed objective function. Computational fluid dynamics was used to calculate the responses for each sample. The parametric study showed that the anticipated variation of the shape of the hill-chart, needed to improve the variable speed performance of the turbine, is limited within a narrow range. The presented method is general and can be applied to any specific speed in the Francis turbine range, for both synchronous speed and variable speed optimization tasks.

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Section: Introductionmentioning

confidence: 99%

Optimization of Francis Turbines for Variable Speed Operation Using Surrogate Modeling Approach

Iliev

Tengs²,

Trivedi³

et al. 2020

Journal of Fluids Engineering

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show abstract

“…Back in 1987, several turbine types were tested to investigate if variable speed could increase performance (Farell & Gulliver, 1987). More recent investigations into variable speed utilize computational tools and show the possibility of increasing the efficiency at off-design conditions (Abubakirov et al, 2013). Power plants with large variations in head will also gain from variable speed operation, as seen in Pérez, Wilhelmi, and Maroto (2008).…”

Section: Introductionmentioning

confidence: 99%

Optimization procedure for variable speed turbine design

Tengs

Storli

Holst

2018

Engineering Applications of Computational Fluid Mechanics

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This article outlines a design procedure for variable speed Francis turbines using optimization software. A fully parameterized turbine design procedure is implemented in MATLAB . ANSYS CFX is used to create hill diagrams for each turbine design. An operation mode of no incidence losses is chosen, and the mean efficiency in the range ±20% of the best efficiency point is used as optimization criterion. This characteristic is extracted for each design, and optiSLang is used for system coupling and optimization. In the global optimization loop, the downhill simplex method is used to maximize the turbine performance. For this article, the bounding geometry of the runner is kept as in the original configuration. This way, the performance of the different variable speed turbines can be compared directly. Two optimization parameters describing the blade leading-edge geometry have been used in the optimization procedure. The resulting design was an almost circular leading edge, and shows an increase in mean efficiency of 0.25% compared to the reference case. There was a significant change in the turbine performance, with close to no change at the best efficiency point, and an increase in efficiency of almost 1% at low rotational speed. The outlined procedure is parallelizable and can be performed within an industrial timeframe. ARTICLE HISTORY

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Improving the Energy Efficiency of Pumped-Storage Power Plants

Artyukh

Galat

Kuzmin³

et al. 2015

Power Technol Eng

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Possible ways to improve the energy efficiency of hydroelectric generating sets of pumped-storage power plants (PSPPs) are studied. The Kiev PSPP is used as an example to show how its generating sets can be upgraded. It is concluded based on studies conducted that synchronous motor-generators should be replaced with asynchronized motor-generators. The feasibility of changing over the turbine to variable-speed operation is shown.National and international experience suggests that reversible hydroelectric generating sets of pumped-storage power plants (PSPPs) built in the 1980s are equipped with synchronous motor-generators (SMG) usually integrated with radial-axial turbines.Since the 1990s, a number of countries have conducted studies related to the improvement of the efficiency of hydroelectric generating sets operating over wide pressure head ranges [1 -3]. These studies show that the efficiency of hydroelectric generating sets can be improved substantially by changing over their turbines to variable-speed operation.This conclusion was successfully validated at a number of Japanese and European PSPPs [4]. Changing over hydroelectric generating sets to variable-speed operation improves their efficiency by 3 to 5%, the range of variation in pressure head being wide (from H r to 0.5H r ).To change over a water turbine to variable-speed operation and to generate electric power of prescribed quality (U = U r , f = f r ), designers had to develop special converting devices. Depending on the amount of change in the turbine speed, the role of such converters may be played by reduction gears, oil clutches, pole-changing generators, thyristor power converters (TPC) in the stator circuit of synchronous machines, and asynchronized generators (AG). An analysis of the strengths and weaknesses of such converting devices reveals that TPCs and AGs are only practicable at real PSPPs.Over the last 10 years, some world's leading companies (Hitachi, Mitsubishi, Andritz) have manufactured and put into operation more than 20 asynchronized motor-generators (AMGs) at a number of 60 to 400 MW PSPPs of Japan, Germany, and Slovakia. In Russia, studies on the use of AMGs at Russian power plants were initiated by the RusHydro Company and have been conducted for five years now.The use of thyristor power converters involves a number of problems [5] such as their high cost for high-power hydroelectric generating sets and need for additional space at the PSPP to accommodate them.The studies conducted by the VNIIE (currently the R&D Center of FGC UES) made it possible to create, in cooperation with the Élektrotyazhmash (Kharkov) and Élektrosila (St. Petersburg) plants, asynchronized turbogenerators and condensers [6,7]. After manufacturing and commissioning the first-ever asynchronized generator at the Iova HPP in the 1960s [8], there were no further developments of asynchronized generators.The use of AMGs at PSPPs allows generating electric power of required quality in both voltage and f r equency, irre-

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Performance Optimization of Hydraulic Turbine by Use of Variable Rotating Speed

Cited by 9 publications

References 1 publication

Optimization of Francis Turbines for Variable Speed Operation Using Surrogate Modeling Approach

Optimization of Francis Turbines for Variable Speed Operation Using Surrogate Modeling Approach

Optimization procedure for variable speed turbine design

Improving the Energy Efficiency of Pumped-Storage Power Plants

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