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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Research-Article
Guide-Vane Closing Schemes for Pump-Turbines Based on Transient Characteristics in S-shaped Region
Wei Zeng,
Wei Zeng
State Key Laboratory of Water Resources and
Hydropower Engineering Science,
Wuhan University,
Wuhan 430072, China
e-mail: wzeng@whu.edu.cn
Hydropower Engineering Science,
Wuhan University,
Wuhan 430072, China
e-mail: wzeng@whu.edu.cn
Search for other works by this author on:
Jiandong Yang,
Jiandong Yang
State Key Laboratory of Water Resources and
Hydropower Engineering Science,
Wuhan University,
Wuhan 430072, China
e-mail: jdyang@whu.edu.cn
Hydropower Engineering Science,
Wuhan University,
Wuhan 430072, China
e-mail: jdyang@whu.edu.cn
Search for other works by this author on:
Jinhong Hu,
Jinhong Hu
State Key Laboratory of Water Resources and
Hydropower Engineering Science,
Wuhan University,
Wuhan 430072, China
e-mail: jinhonghu@whu.edu.cn
Hydropower Engineering Science,
Wuhan University,
Wuhan 430072, China
e-mail: jinhonghu@whu.edu.cn
Search for other works by this author on:
Jiebin Yang
Jiebin Yang
State Key Laboratory of Water Resources and
Hydropower Engineering Science,
Wuhan University,
Wuhan 430072, China
e-mail: jbyang830212@whu.edu.cn
Hydropower Engineering Science,
Wuhan University,
Wuhan 430072, China
e-mail: jbyang830212@whu.edu.cn
Search for other works by this author on:
Wei Zeng
State Key Laboratory of Water Resources and
Hydropower Engineering Science,
Wuhan University,
Wuhan 430072, China
e-mail: wzeng@whu.edu.cn
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
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
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
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. May 2016, 138(5): 051302 (11 pages)
Published Online: January 8, 2016
Article history
Received:
March 11, 2015
Revised:
October 19, 2015
Citation
Zeng, W., Yang, J., Hu, J., and Yang, J. (January 8, 2016). "Guide-Vane Closing Schemes for Pump-Turbines Based on Transient Characteristics in S-shaped Region." ASME. J. Fluids Eng. May 2016; 138(5): 051302. https://doi.org/10.1115/1.4032069
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