Flexible electricity demand and variability of the electricity produced by wind turbines and photovoltaic affect the stable operations of power grids. Pump-turbines are used to stabilize the power grid by maintaining a real-time electricity demand. Consistently, the machines experience transient conditions during the course of operation, such as start-up, load acceptance, load rejection, and shutdown, which induce high amplitude pressure pulsations and affect operating lifespan of the components. During the closure of the wicket gates, the transient flow characteristics is analyzed for a Francis-type reversible pump-turbine in generating mode by three-dimensional (3D) numerical simulation with a moving mesh technique and using detached eddy simulation (DES) turbulent model. Mesh motion is carried out in the region of wicket gates during the load rejection by a moving, sliding mesh, which makes dynamic flow simulation available, instead of building various steady models with different guide vanes angles. The transient flow characteristics are illustrated by analyzing the flow, torque, and pressure fluctuations signals by frequency and time–frequency analyses. The flow field analysis includes the onset and strengthening of unsteady phenomena during the turbine load reduction. The flow pattern in return channel maintained a quite stable flow field, whereas the flow pattern in the runner and draft tube emphasized its instability with the flow rate decreased. Influence of 3D unsteady flow structures on runner is determined, and its evolution is characterized spectrally during fast closure of wicket gates.

References

References
1.
Caralis
,
G.
,
Papantonis
,
D.
, and
Zervos
,
A.
,
2012
, “
The Role of Pumped Storage Systems Towards the Large Scale Wind Integration in the Greek Power Supply System
,”
Renewable Sustainable Energy Rev.
,
16
(
5
), pp.
2558
–25
65
.
2.
Pérez-Díaz
,
J. I.
,
Cavazzini
,
G.
,
Blázquez
,
F.
,
Platero
,
C.
,
Fraile-Ardanuy
,
J.
,
Sánchez
,
J. A.
, and
Chazarra
,
M.
,
2014
, “
Technological Developments for Pumped-Hydro Energy Storage
,” Mechanical Storage Subprogramme, Joint Programme on Energy Storage, European Energy Research Alliance, Brussels, Belgium,
Technical Report
.https://www.eera-set.eu/wp-content/uploads/Technological-Developments-for-Pumped-Hydro-Energy-Storage_EERA-report-2014.pdf
3.
Taulan
,
J. P.
,
Laurier
,
P.
,
Bourrilhon
,
M.
, and
Bornard
,
L.
,
2009
, “
Pump-Turbine Integration in Renewable Energy Systems
,” Waterpower XVI Conference, Spokane, WA, July 27–30, Paper No. 114.
4.
Brauner
,
G.
,
2012
, “
Wege Zur Nachhaltigen Energieversorgung—Herausforderung an Speicher Und Thermische Kraftwerke (Path to Renewable Energy Supply—Challenge for Energy Storage and Thermal Power Stations)
,”
12th Symposium Energy Innovations
, Graz, Austria, Mar. 15–17, pp. 1–9.
5.
VDE Study
,
2012
, “
Flexibilization of Power Generation for Renewable Energy Systems (Erneuerbare Energie Braucht Flexible Kraftwerke—Szenarien bis 2020)
,” ETG-Task Force Flexibilisierung des Kraftwerksparks, Frankfurt, Germany.
6.
SEC
85/3,
2008
, “
Package of Implementation Measures for the EU's Objective on Climate Change and Renewable Energy for 2020
,” Commission of the European Communities, Brussels, Belgium, Report No.
SEC 85-3
.http://ec.europa.eu/transparency/regdoc/rep/2/2008/EN/2-2008-85-EN-1-0.Pdf
7.
Beurskens
,
L. M. W.
, and
Hekkenberg
,
M.
,
2011
, “
Renewable Energy Projections as Published in the National Renewable Energy Action Plans of the European Member States
,” European Environment Agency, Copenhagen, Denmark, Report No.
ECN-E-10-069
.https://www.ecn.nl/docs/library/report/2010/e10069.pdf
8.
Ardizzon
,
G.
,
Cavazzini
,
G.
, and
Pavesi
,
G.
,
2014
, “
A New Generation of Small Hydro and Pumped-Hydro Power Plants: Advances and Future Challenges
,”
Renewable Sustainable Energy Rev.
,
31
, pp.
746
761
.
9.
Pavesi
,
G.
,
Cavazzini
,
G.
, and
Ardizzon
,
G.
,
2016
, “
Numerical Analysis of the Transient Behaviour of a Variable Speed Pump-Turbine During a Pumping Power Reduction Scenario
,”
Energies
,
9
(
7
), pp.
534
544
.
10.
Nilsson
,
O.
, and
Sjelvgren
,
D.
,
1997
, “
Hydro Unit Start-Up Costs and Their Impact on the Short Term Scheduling Strategies of Swedish Power Producers
,”
IEEE Trans. Power Syst.
,
12
(
1
), pp.
38
44
.
11.
Nicolle
,
J.
,
Giroux
,
A. M.
, and
Morissette
,
J. F.
,
2014
, “
CFD Configurations for Hydraulic Turbine Startup
,”
27th IAHR Symposium Hydraulic Machinery and Systems
, Montreal, QC, Canada, Sept. 22–26, p. 032021.
12.
Gagnon
,
M.
,
Jobidon
,
N.
,
Lawrence
,
M.
, and
Larouche
,
D.
,
2014
, “
Optimization of Turbine Startup: Some Experimental Results From a Propeller Runner
,”
27th IAHR Symposium Hydraulic Machinery and Systems
, Montreal, QC, Canada, Sept. 22–26, p. 032022.
13.
Amiri
,
K.
,
Mulu
,
B.
,
Raisee
,
M.
, and
Cervantes
,
M. J.
,
2014
, “
Load Variation Effects on the Pressure Fluctuations Exerted on a Kaplan Turbine Runner
,”
27th IAHR Symposium Hydraulic Machinery and Systems
, Montreal, QC, Canada, Sept. 22–26, p. 032005.
14.
Trivedi
,
C.
,
Cervantes
,
M.
,
Dahlhaug
,
O.
, and
Gandhi
,
B.
,
2015
, “
Experimental Investigation of a High Head Francis Turbine During Spin-No-Load Operation
,”
ASME J. Fluids Eng.
,
137
(
6
), p.
061106
.
15.
Trivedi
,
C.
,
Cervantes
,
M.
,
Gandhi
,
B.
, and
Dahlhaug
,
O.
,
2014
, “
Transient Pressure Measurements on a High Head Model Francis Turbine During Emergency Shutdown, Total Load Rejection, and Runaway
,”
ASME J. Fluids Eng.
,
136
(
12
), p. 121107.
16.
Trivedi
,
C.
,
Cervantes
,
M. J.
, and
Gandhi, B.
, and
Dahlhaug
,
O.
,
2014
, “
Pressure Measurements on a High-Head Francis Turbine During Load Acceptance and Rejection
,”
J. Hydraul. Res.
,
52
(2), pp.
283
297
.
17.
Trivedi
,
C.
,
Cervantes
,
M. J.
, and
Gandhi
,
B. K.
,
2016
, “
Numerical Investigation and Validation of a Francis Turbine at Runaway Operating Conditions
,”
Energ.
,
9
(
3
), p. 22.
18.
Trivedi
,
C.
,
Gandhi
,
B.
, and
Cervantes
,
M.
,
2013
, “
Effect of Transients on Francis Turbine Runner Life: A Review
,”
J. Hydraul. Res.
,
51
(
2
), pp.
121
132
.
19.
Kolšek
,
T.
,
Duhovnik
,
J.
, and
Bergant
,
A.
,
2006
, “
Simulation of Unsteady Flow and Runner Rotation During Shut-Down of an Axial Water Turbine
,”
J. Hydraul. Res.
,
44
(
1
), pp.
129
137
.
20.
Melot
,
M.
,
Monette
,
C.
,
Coutu
,
A.
, and
Nenneman
,
B.
,
2013
, “
Speed No-Load Operating Condition: A New Standard Francis Runner Design Procedure to Predict Static Stresses
,”
XVIII Conference on Hydraulics, Water Resources, Coastal and Environmental Engineering, Innsbruck
, Austria, Dec. 4–6, pp.
1
8
.
21.
Côté
,
P.
,
Dumas
,
G.
,
Moisan
,
E.
, and
Boutet-Blais
,
G.
,
2014
, “
Numerical Investigation of the Flow Behavior Into a Francis Runner During Load Rejection
,”
27th IAHR Symposium Hydraulic Machinery and Systems
, Montreal, QC, Canada, Sept. 22–26, p. 032023.
22.
Xiao
,
J. L.
,
Zhu
,
E. Q.
, and
Wang
,
G. D.
,
2012
, “
Numerical Simulation of Emergency Shutdown Process of Ring Gate in Hydraulic Turbine Runaway
,”
ASME J. Fluids Eng.
,
134
(
12
), p.
124501
.
23.
Trivedi
,
C.
,
Gandhi
,
B.
,
Cervantes
,
M.
, and
Dahlhaug
,
O.
,
2015
, “
Experimental Investigations of a Model Francis Turbine During Shutdown at Synchronous Speed
,”
Renewable Energy
,
83
, pp.
828
836
.
24.
Kuwabara
,
T.
,
Katayama
,
K.
,
Nakagawa
,
H.
, and
Hagiwara
,
H.
,
2000
, “
Improvements of Transient Performance of Pump Turbine Upon Load Rejection
,” Power Engineering Society Summer Meeting (
PESS
), Seattle, WA, July 16–20, pp.
1783
1788
.
25.
Trivedi
,
C.
,
Cervantes
,
M.
,
Gandhi
,
B.
, and
Dahlhaug
,
O.
,
2014
, “
Experimental Investigations of Transient Pressure Variations in a High Head Model Francis Turbine During Start-Up and Shutdown
,”
J. Hydrodyn.
,
26
(
2
), pp.
277
290
.
26.
Nicolet
,
C.
,
Alligné
,
S.
,
Kawkabani
,
B.
,
Koutnik
,
J.
,
Simond
,
J.-J.
, and
Avellan
,
F.
,
2009
, “
Stability Study of Francis Pump-Turbine at Runaway
,” Third Meeting IAHR Workgroup on Cavitation and Dynamic Problems in Hydraulic Machinery and Systems, Brno, Czech Republic, Oct. 14–16, Paper No.
EPFL-CONF-163857.
http://www.powervision-eng.ch/Simsen_hydro/Publications/pdf/IAHR_WG1_2009_1.pdf
27.
Yin
,
J. L.
,
Wang
,
D. Z.
,
Wei
,
X. Z.
, and
Wang
,
L. Q.
,
2013
, “
Hydraulic Improvement to Eliminate S-Shaped Curve in Pump Turbine
,”
ASME J. Fluids Eng.
,
135
(
7
), p.
071105
.
28.
Zeng
,
W.
,
Yang
,
J.
, and
Guo
,
W.
,
2015
, “
Runaway Instability of Pump-Turbines in S-Shaped Regions Considering Water Compressibility
,”
ASME J. Fluids Eng.
,
137
(
5
), p.
051401
.
29.
Yao
,
Z.
,
Bi
,
H. L.
,
Huang
,
Q. S.
,
Li
,
Z. J.
, and
Wang
,
Z. W.
,
2013
, “
Analysis on Influence of Wicket Gates Closure Laws of Pump-Turbine on Load Rejection Transient Process
,” IOP Sixth International Conference on Pumps and Fans With Compressors and Wind (
ICPF
), Beijing, China, Sept. 19–22, pp.
66
71
.
30.
Yang
,
J.
,
Pavesi
,
G.
,
Yuan
,
S.
,
Cavazzini
,
G.
, and
Ardizzon
,
G.
,
2015
, “
Experimental Characterization of a Pump–Turbine in Pump Mode at Hump Instability Region
,”
ASME J. Fluids Eng.
,
137
(
5
), p. 051109.
31.
Cavazzini
,
G.
,
Pavesi
,
G.
, and
Ardizzon
,
G.
,
2011
, “
Pressure Instabilities in a Vaned Centrifugal Pump
,”
Proc. Inst. Mech. Eng., Part A
,
225
(
7
), pp.
930
939
.
32.
Cavazzini
,
G.
,
Covi
,
A.
,
Pavesi
,
G.
, and
Ardizzon
,
G.
,
2016
, “
Analysis of the Unstable Behavior of a Pump-Turbine in Turbine Mode: Fluid-Dynamical and Spectral Characterization of the S-Shape Characteristic
,”
ASME J. Fluids Eng.
,
138
(
2
), p.
021105
.
33.
Menter
,
F. R.
, and
Kuntz
,
M.
, 2003, “
Development and Application of a Zonal DES Turbulence Model for CFX-5—CFX-Validation Report
,” ANSYS, Canonsburg, PA, Report No. CFX-VAL17/0503.
34.
Yan
,
J.
,
Koutnik
,
J.
,
Seidel
,
U.
, and
Hübner
,
B.
,
2010
, “
Compressible Simulation of Rotor-Stator Interaction in Pump-Turbines
,”
Int. J. Fluid Mach. Syst.
,
3
(4), pp. 315–323.
35.
Yin
,
J. L.
,
Wang
,
D. Z.
,
Wang
,
L. Q.
,
Wu
,
Y. L.
, and
Wei
,
X. Z.
,
2010
, “
Effects of Water Compressibility on the Pressure Fluctuation Prediction in Pump Turbine
,”
IOP Conf. Ser.: Earth Environ. Sci.
,
15
(
6
), p. 062030.
36.
Kurzin
,
V. B.
,
2013
, “
Effect of Water Compressibility on Nonstationary Characteristics of Hydraulic Turbines
,”
J. Eng. Phys. Thermophys.
,
86
(
5
), pp.
1202
1209
.
37.
Xiaoqin
,
L.
,
Jinshi
,
C.
, and
Peng
,
C.
,
2013
, “
Wicket Gate Closure Control Law to Improve the Transient of a Water Turbine
,”
Adv. Mater. Res.
,
732–733
, pp.
451
456
.
38.
Cui
,
H. C.
,
Fan
,
H. G.
, and
Chen
,
N. X.
,
2012
, “
Optimization of Wicket-Gate Closing Law Considering Different Cases
,”
IOP Conf. Ser.: Earth Environ. Sci.
,
15
(5), p. 052008.
39.
Cuzmoş
,
A.
,
Câmpian
,
C. V.
,
Frunzăverde
,
D.
,
Dumbravă
,
C.
, and
Budai
,
A. M.
,
2015
, “
Tests Performed on Hydraulic Turbines at Commissioning or After Capital Repair—Part I: Tests Performanced on a 78-MW Francis Turbine
,” Analele Universităţii “Eftimie Murgu” Fascicula de Inginerie ANUL XXII, Vol. 1, pp.
1453
7397
.
You do not currently have access to this content.