Evolutions of guide vane moment of a pump-turbine during runaway transient process after pump trip

Zheng, Yang; Cheng, Yongguang; Xia, Linsheng; Meng, Wanwan; Gao, Lili; Dai, Yongqian

doi:10.1088/1755-1315/240/7/072033

Cited by 4 publications

(1 citation statement)

References 3 publications

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“…To undertake these important functions, the stability and safety of pumped-storage power systems are essential. However, some stability problems in operating pumped-storage power stations, such as violent vibration of pump-turbine units [6], grid connection failure [7,8], runner lifting-up [9], and rotor-stator crashing [10], were frequently reported. These problems were generally attributed to the frequent conversions of operating conditions, especially when the working points pass through the so-called S-and hump-shaped characteristics regions, in which intense flow and pressure fluctuations occur.…”

Section: Introductionmentioning

confidence: 99%

Differences of Flow Patterns and Pressure Pulsations in Four Prototype Pump-Turbines during Runaway Transient Processes

et al. 2020

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Frequent working condition conversions in pumped-storage power stations often induce stability problems, especially when the operating point enters the S-shaped region, during which flow transitions and pressure fluctuations are serious. The pump-turbines with different specific speed values show different characteristics, but their differences in stability features are still not clear. In this study, four different pump-turbines were selected to simulate the runaway processes from turbine modes. The similarities and differences of flow patterns and pressure fluctuations were analyzed. For the similarities, pressure pulsations increase gradually and fluctuate suddenly once the backflows occur at the runner inlets. For the differences, the evolutions of backflows and pressure pulsations are related to specific speeds and runner shapes. Firstly, it is easier for the lower specific speed turbines to enter the reverse pump mode. Secondly, the blade lean angle influences the position where backflows occur, because it determines the pressure gradient at the runner inlets. Thirdly, the runner inlet height influences pressure pulsations in the vaneless space, because the relative range of backflow transitions will be enlarged with the decrease of specific speed. Overall, investigating the mechanisms of flow pattern transitions and pressure variations is important for runner design and transient process control.

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Section: Introductionmentioning

confidence: 99%

Differences of Flow Patterns and Pressure Pulsations in Four Prototype Pump-Turbines during Runaway Transient Processes

et al. 2020

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Numerical investigation on characteristics of transient process in centrifugal pumps during power failure

Feng

Zhang

et al. 2021

Renewable Energy

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Review of Research on the Three-Dimensional Transition Process of Large-Scale Low-Lift Pump

Zhang

et al. 2022

Energies

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Due to the uneven distribution of water resources, there are many water diversion projects around the world, such as the South-to-North Water Diversion Project in China, especially in some plain areas. To transfer water from low to high areas, large low-head pumps have been widely used. The transition process of the pumping station is mainly caused by the sudden change in the flow velocity and pressure of the fluid in the pipeline of the pumping station system caused by the start-up and shutdown processes. The previous research has mainly been based on the one-dimensional characteristic line method. However, due to the characteristics of the low-lift pumping station, the flow passage is short and irregular, and the calculation results often cannot guarantee the accuracy of the calculation. In addition to some faults in the actual operation process, in some pumping stations, accidents or operation-scheduling faults are caused by transient processes, such as a high degree of water hammer, the inability to initiate backward flow, the shutdown load rejection runaway exceeding the standard, and decreased hydraulic efficiency. To avoid transition process failures in the newly designed pumping stations and the modified pumping stations, it is necessary to carry out a research review of the three-dimensional transition process of large low-lift pumps. Especially with the development of computing technology, CFD numerical simulation technology has become the main research method for analyzing the pump transition process. The research on the transition process is mainly based on the combination of numerical simulations and experiments. The reliability of a numerical simulation is verified by an experiment. A numerical simulation can measure some parameters that cannot be measured by an experiment. Dynamic mesh technology has become the main technical means for using CFD numerical simulation to study the three-dimensional transition process, and the secondary development of computing software has become the main trend of future development. This paper analyzes and summarizes the research status of the start–stop transition process of large low-lift pump stations and provides a reference for the protection of the start–stop transition process of pump stations.

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Evolutions of guide vane moment of a pump-turbine during runaway transient process after pump trip

Cited by 4 publications

References 3 publications

Differences of Flow Patterns and Pressure Pulsations in Four Prototype Pump-Turbines during Runaway Transient Processes

Differences of Flow Patterns and Pressure Pulsations in Four Prototype Pump-Turbines during Runaway Transient Processes

Numerical investigation on characteristics of transient process in centrifugal pumps during power failure

Review of Research on the Three-Dimensional Transition Process of Large-Scale Low-Lift Pump

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