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Research Papers: Multiphase Flows

Guide-Vane Closing Schemes for Pump-Turbines Based on Transient Characteristics in S-shaped Region

[+] Author and Article Information
Wei Zeng

State Key Laboratory of Water Resources and
Hydropower Engineering Science,
Wuhan University,
Wuhan 430072, China
e-mail: wzeng@whu.edu.cn

Jiandong Yang

State Key Laboratory of Water Resources and
Hydropower Engineering Science,
Wuhan University,
Wuhan 430072, China
e-mail: jdyang@whu.edu.cn

Jinhong Hu

State Key Laboratory of Water Resources and
Hydropower Engineering Science,
Wuhan University,
Wuhan 430072, China
e-mail: jinhonghu@whu.edu.cn

Jiebin Yang

State Key Laboratory of Water Resources and
Hydropower Engineering Science,
Wuhan University,
Wuhan 430072, China
e-mail: jbyang830212@whu.edu.cn

1Corresponding author.

Contributed by the Fluids Engineering Division of ASME for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received March 11, 2015; final manuscript received October 19, 2015; published online January 8, 2016. Assoc. Editor: Frank C. Visser.

J. Fluids Eng 138(5), 051302 (Jan 08, 2016) (11 pages) Paper No: FE-15-1165; doi: 10.1115/1.4032069 History: Received March 11, 2015; Revised October 19, 2015

During the transitional processes of load rejection in a pumped-storage station, the S-shaped characteristics of the pump-turbines can result in relatively large water-hammer and pulsating pressures. These pressures and the high runaway speed during transient processes may directly damage the penstocks and shorten the life of the turbine. In this study, different guide-vane closing schemes for reducing the maximum transient pressures, including the water-hammer and pulsating pressures, and runaway speed were investigated, and the principles for improving the closing schemes were theoretically analyzed based on the transient characteristics in the S-shaped region. First, an analytical expression for the rate of change of relative water head during the transitional processes was deduced based on a simplified mathematical model. It reveals the relationship between the slopes of the trajectory at the pump-turbine operating points (defined as trajectory slopes) and the rigid water-column pressure, which approximates the water-hammer pressure considering compressibility. Then, based on the characteristics of the rigid water-column pressure during the transient process and the effects of guide-vane closure on the trajectory slopes, the selection method for a two-phase guide-vane closing scheme was proposed. The method included the technique for choosing the coordinates of the turning point and the closing speed of the guide vane. Furthermore, the pulsating pressures of pump-turbines were discussed under different working regions and guide-vane openings (GVOs). Considering the characteristics of the pulsating pressures and the runaway speed during the transient processes, the advantage of three-phase valve-closing schemes in controlling the pulsating pressures and the runaway speed was clarified. Finally, a series of model tests were conducted on a pumped-storage station model and the measured data fully validated the correctness of our analyses in this work.

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References

Zeng, W. , Yang, J. D. , and Guo, W. C. , 2015, “ Runaway Instability of Pump-Turbines in S Shaped Regions Considering Water Compressibility,” ASME J. Fluids Eng., 137(5), p. 051401. [CrossRef]
Widmer, C. , Staubli, T. , Tresch, T. , and Sallaberger, M. , 2010, “ Unstable Pump-Turbine Characteristics and Their Interaction With Hydraulic Systems,” Hydrovision 2010, Charlotte, NC.
Olimstad, G. , Nielsen, T. K. , and Børresen, B. , 2012, “ Stability Limits of Reversible-Pump Turbines in Turbine Mode of Operation and Measurements of Unstable Characteristics,” ASME J. Fluids Eng., 134(11), p. 111202. [CrossRef]
Nicolet, C. , Alligné, S. , Kawkabani, B. , Koutnik, J. , Simond, J.-J. , and Avellan, F. , 2009, “ Stability Study of Francis Pump-Turbine at Runaway,” 3rd IAHR International Meeting of the Workgroup on Cavitation and Dynamic Problems in Hydraulic Machinery and Systems, Brno, Czech Republic, pp. 371–384.
Nicolet, C. , Alligné, S. , Kawkabani, B. , Simond, J.-J. , and Avellan, F. , 2008, “ Unstable Operation of Francis Pump-Turbine at Runaway: Rigid and Elastic Water Column Oscillation Modes,” 24th IAHR Symposium on Hydraulic Machinery and Systems, Foz do Iguassu, Brazil.
Zobeiri, A. , Kueny, J.-L. , Farhat, M. , and Avellan, F. , 2006, “ Pump-Turbine Rotor-Stator Interactions in Generating Mode: Pressure Fluctuation in Distributor Channel,” 23rd IAHR Symposium on Hydraulic Machinery and Systems, Yokohama, Japan.
Sick, M. , Dörfler, P. , Michler, W. , Sallaberger, M. , and Lohmberg, A. , 2004, “ Investigation of the Draft Tube Vortex in a Pump-Turbine,” 22nd IAHR Symposium on Hydraulic Machinery and Systems, Stockholm, Sweden.
Widmer, C. , Staubli, T. , and Ledergerber, N. , 2011, “ Unstable Characteristics and Rotating Stall in Turbine Brake Operation of Pump-Turbines,” ASME J. Fluids Eng., 133(4), p. 041101. [CrossRef]
Hasmatuchi, V. , Farhat, M. , Roth, S. , Botero, F. , and Avellan, F. , 2011, “ Experimental Evidence of Rotating Stall in a Pump-Turbine at Off-Design Conditions in Generating Mode,” ASME J. Fluids Eng., 133(5), p. 051104. [CrossRef]
Cavazzini, G. , Covi, A. , Pavesi, G. , and Ardizzon, G. , 2016, “ Analysis of the Unstable Behavior of a Pump-Turbine in Turbine Mode: Fluids-Dynamical and Spectral Characterization of the S-Shaped Characteristic,” ASME J. Fluids Eng., 138(2), p. 021105. [CrossRef]
Olimstad, G. , Nielsen, T. K. , and Børresen, B. , 2012, “ Dependency on Runner Geometry for Reversible-Pump Turbine Characteristics in Turbine Mode of Operation,” ASME J. Fluids Eng., 134(12), p. 121102. [CrossRef]
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. [CrossRef]
Yang, W. , and Xiao, R. F. , 2013, “ Multiobjective Optimization Design of a Pump–Turbine Impeller Based on an Inverse Design Using a Combination Optimization Strategy,” ASME J. Fluids Eng., 136(1), p. 014501. [CrossRef]
Zeng, W. , Yang, J. D. , and Chen, Y. G. , 2014, “ Construction of Pump-Turbine Characteristics at Any Specific Speed by Domain-Partitioned Transformation,” ASME J. Fluids Eng., 137(3), p. 031103. [CrossRef]
Yang, L. , and Cheng, N. X. , 2003, “ Analysis of Relation Between Characteristics of Pump-Turbine Runner and Transition of Pumped-Storage Power Station,” J. Tsinghua Univ. (Sci. Technol.), 43(10), pp. 1424–1427.
Azoury, P. H. , Baasiri, M. , and Najm, H. , 1986, “ Effect of Valve-Closure Schedule on Water Hammer,” ASCE J. Hydraul. Eng., 112(100), pp. 890–903. [CrossRef]
Yang, J. D. , 1999, “ Optimization of Wicket Closure Rule and Influence on Hydraulic Transients for Water Power Station,” J. Hydroelectr. Eng., 1999(2), pp. 75–83.
Vakil, A. , and Firoozabadi, B. , 2009, “ Investigation of Valve-Closing Law on the Maximum Head Rise of a Hydropower Plant,” Sci. Iran., Trans. B, 16(3), pp. 222–228.
Kuwabara, T. , Katayama, K. , Nakagawa, H. , and Hagiwara, H. , 2000, “ Improvements of Transient Performance of Pump Turbine Upon Load Rejection,” IEEE Power Engineering Society Summer Meeting, Seattle, WA, 3, pp. 1783–1788.
Yu, X. , Zhang, J. , and Miao, D. , 2015, “ Innovative Closure Law for Pump-Turbines and Field Test Verification,” ASCE J. Hydraul. Eng., 141(3), p. 0514010. [CrossRef]
Zhang, J. , Hu, J. Y. , Hu, M. , Fang, J. , and Chen, N. , 2006, “ Study on the Reversible Pump-Turbine Closing Law and Field Test,” ASME Paper No. FEDSM2006-98155, pp. 931–936.
Sao, W. Y. , 2004, “ Numerical Simulation on Hydraulic Transient With MGV in Pumped Storage and Its Application,” Ph.D. thesis, Zhejiang University, Hangzhou, China.
Sun, H. , Xiao, R. F. , Liu, W. C. , and Wang, F. J. , 2013, “ Analysis of S Characteristics and Pressure Pulsations in a Pump-Turbine With Misaligned Guide Vanes,” ASME J. Fluids Eng., 135(5), p. 0511011. [CrossRef]
Suter, P. , 1966, “ Representation of Pump Characteristics for Calculation of Water Hammer,” Sulzer Tech. Rev., 1966(4), pp. 45–48.
Wang, C. , and Yang, J. D. , 2015, “ Water Hammer Simulation Using Explicit-Implicit Coupling Methods,” ASCE J. Hydraul. Eng., 141(4), p. 04014086. [CrossRef]
Wylie, E. B. , and Streeter, V. L. , 1993, Fluid Transients in Systems, Prentice Hall, Englewood Cliffs, NJ.
Yang, W. J. , Yang, J. D. , Guo, W. C. , Zeng, W. , Wang, C. , Saarinen, L. , and Norrlund, P. , 2015, “ A Mathematical Model and Its Application for Hydro Power Units Under Different Operating Conditions,” Energies, 2015(8), pp. 10260–10275. [CrossRef]
Yang, J. B. , and Yang, J. D. , 2012, “ B-Spline Surface Construction for the Complete Characteristics of Pump-Turbine,” IEEE 2012 Asia-Pacific Power and Energy Engineering Conference, Shanghai, China, pp. 1–5.
Trivedi, C. , Cervantes, M. J. , Gandhi, B. K. , and Dahlhaug, O. G. , 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. [CrossRef]
IEC 60193, 1991, Hydraulic Turbines, Storage Pumps and Pump-Turbines–Model Acceptance Tests, International Electrotechnical Commission, Geneva, Switzerland.
Nielsen, T. K. , 1990, “ Transient Characteristics of High Head Francis Turbines,” Ph.D. thesis, Norwegian University of Science and Technology, Trondheim, Norway.
ISO 4185, 1980, Measurement of Liquid Flow in Closed Conduits–Weighing Method, International Organization for Standardization, Geneva, Switzerland.
Schafer, R. W. , 2011, “ What is a Savitzky–Golay Filter,” IEEE Signal Process. Mag., 2011(7), pp. 111–117. [CrossRef]

Figures

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Fig. 1

Statistics of the number of pump-turbine transitional processes

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Fig. 2

Comparison of rigid and elastic water-hammer models for transient simulations: (a) load rejection with servomotor failure and (b) load rejection with guide-vane closure

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Fig. 3

Validation of elastic model

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Fig. 4

Denominator in term J

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Fig. 5

Comparison of 1/a and Sc: (a) load rejection with servomotor failure and (b) load rejection with guide-vane closure

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Fig. 6

Segmentation of S characteristic curve

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Fig. 7

Relationship between guide-vane closure and trajectory slopes

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Fig. 8

Ladderlike guide-vane closing scheme: (a) guide-vane closing scheme and transient pressure in spiral case and (b) trajectory curve

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Fig. 9

Comparison of fast closing and slow closing of guide vanes during the second phase

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Fig. 10

Spectrograms of pulsating pressures for spiral case of PSS2: (a) 75% load rejection and (b) full load rejection

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Fig. 11

Contour plot of peak-to-peak values of pulsating pressures in spiral case of PSS3

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Fig. 12

Three-phase guide-vane closing schemes and transient pressures in spiral case

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Fig. 13

Comparison of runaway speeds: two-phase closing schemes versus three-phase closing schemes

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Fig. 14

Pumped-storage station model

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Fig. 15

Test of the pump-turbine characteristic curve by transient method

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Fig. 16

Comparison of simulated parameters by topsys and experimental data: (a) pressure in the spiral case, (b) pressure in the draft tube, and (c) rotating speed

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Fig. 17

Comparison of transient parameters of PSS4: two-phase closing schemes versus continuous linear closing

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Fig. 18

Comparison of transient parameters: three-phase closing schemes versus two-phase closing scheme

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Fig. 19

Comparison of trajectories under different closing schemes: (a) test 2 versus test 3, (b) test 2 versus test 4, and (c) test 2 versus test 5

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