Pressure Fluctuations in the S-Shaped Region of a Reversible Pump-Turbine

Wang, Zijie; Zhu, Baoshan; Xuhe, Wang; Qin, Daqing

doi:10.3390/en10010096

Cited by 26 publications

(14 citation statements)

References 14 publications

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“…For the large capacity pump-turbine unit, besides the efficiency and cavitation performances, the operation stability for both operating conditions should be guaranteed [3,28]. Under pump mode, instabilities with cavitation in the hump region limit the normal operating range of the unit.…”

Section: Discussionmentioning

confidence: 99%

Parametric Design of an Ultrahigh-Head Pump-Turbine Runner Based on Multiobjective Optimization

et al. 2017

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Pumped hydro energy storage (PHES) is currently the only proven large-scale energy storage technology. Frequent changes between pump and turbine operations pose significant challenges in the design of a pump-turbine runner with high efficiency and stability, especially for ultrahigh-head reversible pump-turbine runners. In the present paper, a multiobjective optimization design system is used to develop an ultrahigh-head runner with good overall performance. An optimum configuration was selected from the optimization results. The effects of key design parameters-namely blade loading and blade lean-were then investigated in order to determine their effects on runner efficiency and cavitation characteristics. The paper highlights the guidelines for application of inverse design method to high-head reversible pump-turbine runners. Middle-loaded blade loading distribution on the hub, back-loaded distribution on the shroud, and large positive blade lean angle on the high pressure side are good for the improvement of runner power performance. The cavitation characteristic is mainly influenced by the blade loading distribution near the low pressure side, and large blade lean angles have a negative impact on runner cavitation characteristics.

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Section: Discussionmentioning

confidence: 99%

Parametric Design of an Ultrahigh-Head Pump-Turbine Runner Based on Multiobjective Optimization

et al. 2017

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“…e transient process model of pumped storage unit was solved by using the method of characteristics, and the basic motion and continuity equation of unsteady flow in pressurized pipeline are shown below [28][29][30][31][32].…”

Section: Methods Of Characteristicsmentioning

confidence: 99%

“…Initialize the parameters of pumped storage unit model and optimize GVCS, select guide vane closing mode, and set parameters of multiobjective genetic algorithmConstruct and initialize the individuals of multiobjective genetic algorithm Pumped storage unit model simulation calculation and calculation of WHP and RSRR by equations(6) and(7)Fast nondominated sorting and calculation of crowding distance by formula(29) and individual quality by formula (31) Process of optimization of GVCS with multiobjective genetic algorithm.…”

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confidence: 99%

Analysis on Guide Vane Closure Schemes of High‐Head Pumped Storage Unit during Pump Outage Condition

Zhang

Zheng

et al. 2019

Mathematical Problems in Engineering

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When the pumping operation of pumped storage unit suffers from power outage, the hydraulic transient poses a serious threat to the safe operation of the unit and its pressure pipeline system. For high-head pumped storage power station (PSPS), the water hammer pressure (WHP) and rotational speed rise ratio (RSRR) of each hydraulic unit will be increased during the pump outage condition. In order to limit the fluctuation of rotational speed and WHP in power-off condition, optimizing and choosing a reasonable guide vane closure scheme (GVCS) is an economic and efficient means to improve the dynamic characteristics of pumped storage unit. On the basis of the calculation model of the transition process of single tube-double unit type of a high-head PSPS, an optimization model of GVCS balancing WHP and RSRR objectives is established. Furthermore, the two-stage broken line and three-stage delayed GVCSs are applied to the pump outage condition, and the nondominated sorting genetic algorithm-II (NSGA-II) is introduced to calculate the optimal solution set under different water heads and different closure schemes. For four typical water heads, the multiobjective optimization results of the closure law show that the two-stage broken line law has a better Pareto front under high water head, while the three-stage delayed law has a better performance under low water head. Furthermore, through the results of transition process of typical schemes, the adaptability of GVCS and water head is analyzed. The method proposed in this paper can make the RSRR not more than −0.89, and the three-stage delayed law can even make the RSRR only −0.01. Methods of this paper provide a theoretical basis for optimum guide vane closure mode setting of PSPS.

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“…During the dynamic process of extreme condition (i.e. load rejection or pump outage) with the non optimal closing law, the rise of the unit rotational speed and the water hammer pressure will exceed the maximum design value, which cause the runaway speed of the PSHU, abnormal vibration or active guide vane asynchronous and other negative phenomena [8,9]. OGVCS plays an important role in ensuring the security and stability of the power grid, and several methods have been proposed to deal with the OGVCS problem.…”

Section: Of 26mentioning

confidence: 99%

Optimization of Guide Vane Closing Schemes of Pumped Storage Hydro Unit Using an Enhanced Multi-Objective Gravitational Search Algorithm

Zhou¹,

Xu²,

Zheng³

et al. 2017

Preprint

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Abstract：The optimization of guide vane closing schemes (OGVCS) of pumped storage hydro unit (PSHU) is the research field of cooperative control and optimal operation of pumped storage, wind power and solar power generation. This paper presents a OGVCS model of PSHU considering the rise rate of the unit rotational speed and the specific node pressure of each hydraulic unit, as well as various complicated hydraulic and mechanical constraints. OGVCS model is formulated as a multi-objective optimization problem to optimize conflictive objectives, i.e., unit rotational speed and water hammer pressure criteria. In order to realize the efficient solution of the OGVCS model, an enhanced multi-objective bacterial-foraging chemotaxis gravitational search algorithm (EMOBCGSA) is proposed to solve this problem, which adopts population reconstruction, adaptive selection chemotaxis operator of local searching strategy and Elite archive set to efficiently solve the multi-objective problem. Especially, novel constraints-handling strategy with eliminating and local search based on violation ranking is used to balance various hydraulic and mechanical constraints. Finally, simulation cases of complex extreme operating conditions (i.e., load rejection and pump outage) of 'single tube-double units' type PSHU system are conducted to verify the feasibility and effectiveness of the proposed EMOBCGSA in solving OGVCS problem. The simulation results indicate that the proposed EMOBCGSA can provide lower rise rate of the unit rotational speed and smaller water hammer pressure than other method established recently while considering various complex constraints in OGVCS problem.Keyword: pumped storage hydro unit; guide vane closing schemes; multi-objective optimization; enhanced multi-objective bacterial-foraging chemotaxis gravitational search algorithm (EMOBCGSA); hydraulic and mechanical constraints

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Pressure Fluctuations in the S-Shaped Region of a Reversible Pump-Turbine

Cited by 26 publications

References 14 publications

Parametric Design of an Ultrahigh-Head Pump-Turbine Runner Based on Multiobjective Optimization

Parametric Design of an Ultrahigh-Head Pump-Turbine Runner Based on Multiobjective Optimization

Analysis on Guide Vane Closure Schemes of High‐Head Pumped Storage Unit during Pump Outage Condition

Optimization of Guide Vane Closing Schemes of Pumped Storage Hydro Unit Using an Enhanced Multi-Objective Gravitational Search Algorithm

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