scholarly journals Analysis of Rotor-Stator Interaction of a Pump-Turbine with Splitter Blades in a Pump Mode

Mathematics ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1465 ◽  
Author(s):  
Haiqin Song ◽  
Jinfeng Zhang ◽  
Ping Huang ◽  
Haikun Cai ◽  
Puyu Cao ◽  
...  
Keyword(s):  
Radial Force ◽  
Stable Operation ◽  
Power Station ◽  
Pump Turbine ◽  
Main Frequency ◽  
Pulsation Amplitude ◽  
Depth Analysis ◽  
Rotor Stator Interaction ◽  
Guide Blade ◽  
Pumped Storage

The pump-turbine is the core component of a pumped storage power station. This paper considers an in-depth analysis of the rotor-stator interaction characteristics under computational fluid dynamics (CFD) and experimental measurements of pump-turbine with splitter blades used in a domestic pumped storage power station. The results show that as the guide blade opening increases, the rotor-stator interaction of the pump-turbine intensifies and the magnitude of the runner radial force and its pulsation amplitude as well as the magnitude of the guide blade water moment and its pulsation amplitude also increase. In addition, when the opening degree increases from 9.8° to 17.5°, the influence on the main frequency is mainly reflected in the phase change. While the opening degree increases from 17.5° to 24.8°, the influence on the main frequency is mainly reflected in the amplitude change. Moreover, the amplitude of 5fn at opening 9.8° and opening 24.8° is greater than the optimal opening 17.5°, indicating that deviation from the optimal opening will aggravate the difference of rotor-stator interaction between splitter blades and guide blades. In the paper, the influence of guide blade openings on the rotor-stator interaction between the splitter guide blade is studied, which provides a theoretical reference for the stable operation of the pump-turbine.

Study of flow characteristics in the S-shaped region of a pump-turbine at Baoquan pumped storage power station

2015 ◽  
Vol 10 (2) ◽  
pp. 242-249
Author(s):  
Jun Li ◽  
Yongmei Cao ◽  
Lei Wang ◽  
Xiaochong Chen
Keyword(s):  
Cfd Simulation ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Modern Society ◽  
Stable Operation ◽  
Power Station ◽  
Pump Turbine ◽  
Research Findings ◽  
Computational Fluid Dynamics Cfd ◽  
Pumped Storage

Pumped storage power plays increasingly important roles in modern society but requires some complex equipment. The characteristics of the S-shaped region of a reversible pump-turbine caused significant difficulties in the stable operation of the unit. In this paper, the 1# pump-turbine at Baoquan storage power station is studied. The basic variations of the internal flow were understood using Computational Fluid Dynamics (CFD) simulation, and the relationship between head variation and the ‘S’ characteristic was analyzed. It was found that the basis of the ‘S’ characteristics was channel congestion caused by vortices. Methods that might be used to eliminate the effects of the ‘S’ characteristic are also given. The authors believe that the research findings in this paper could provide the technical support needed for stable operation of such units, as well as further studies of the ‘S’ characteristic.

Study on the Relationship between Ergometer and Tensioning Force of Pre-Stressed Pier Anchor Cable

2013 ◽  
Vol 353-356 ◽  
pp. 2822-2826
Author(s):  
Jun Xing ◽  
Zhi Xin Fan
Keyword(s):  
Stable Operation ◽  
Indicator Values ◽  
Power Station ◽  
Anchor Cable ◽  
Lower Reservoir ◽  
The Difference ◽  
Pumped Storage ◽  
The Relationship

During the construction of pre-stressed anchor cables for discharging flood and sand in the lower reservoir of Pushihe Pumped-storage Power Station, the tensioning of main and secondary cables are overall carried out according to design, in which the tensioning force is divided into seventh grades, the indicator values of ergometer and tensioning force of jack were obtained by experiment, and the difference between them were compared and analysis, the results of experiment provides the basis for the long-term and stable operation of pre-stressed pier in Pushihe project.

scholarly journals Nonlinear Modeling of Dynamic Characteristics of Pump-Turbine

Energies ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 297
Author(s):  
Liying Wang ◽  
Kaidi Zhang ◽  
Weiguo Zhao
Keyword(s):  
Linear Model ◽  
Nonlinear Model ◽  
Dynamic Characteristics ◽  
Clean Energy ◽  
Energy Development ◽  
Stable Operation ◽  
Storage Unit ◽  
Pump Turbine ◽  
Characteristic Model ◽  
Pumped Storage

Hydropower is a kind of clean energy, which can effectively reduce the consumption of fossil energy and is one of the main fields of new energy development. Pumped storage power station not only provides a solution for storing electric energy and generating excess, but also is a clean, efficient, economical and safe power system regulation method with high quality. Accurate modeling of a pump-turbine, as the core equipment of a pumped storage unit, is the key to safe and stable operation of the pumped storage unit. At present, a method of simplifying the external characteristics of a pump-turbine into a first-order linear model is widely used, which cannot effectively and accurately reveal the nonlinear dynamic characteristics of the unit in transition process. In order to meet the demand of high-precision simulation of the unit, a new method of identifying Taylor series expansion considering nonlinearity based on the torque characteristic formula and the flow characteristic formula is proposed, which is applied to the pump-turbine external characteristic model, and retains the second derivative term, making the model a second-order nonlinear model, and thus, the pump-turbine model becomes a nonlinear model. The nonlinear model established is used to simulate the load increase and load rejection of the unit, and the results are compared with those for the linear model. The comparison shows that the nonlinear model established for the pump-turbine can reveal the dynamic response of the unit more effectively and accurately than the linear model, and provide a further guarantee for the safe and stable operation of pumped-storage units, which is of great significance to hydropower energy development.

The hydraulic design of pump turbine for Xianyou pumped storage power station

2012 ◽  
Vol 15 (3) ◽  
pp. 032035
Author(s):  
J S Zheng ◽  
W C Liu ◽  
Z Y Fu ◽  
Q H Shi
Keyword(s):  
Power Station ◽  
Pump Turbine ◽  
Hydraulic Design ◽  
Pumped Storage

scholarly journals Characteristic Analysis and Optimal Regulation of Primary Frequency Regulation Condition in Low Water Head Area Based on Hydraulic-Mechanical-Electrical Coupling Model of Pumped Storage Unit

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-17 ◽  
Author(s):  
Cong Lv ◽  
Yanhe Xu ◽  
Xin Wu ◽  
Qing Zhang
Keyword(s):  
Power Grid ◽  
Electrical Coupling ◽  
Frequency Regulation ◽  
Regulation System ◽  
Optimization Strategy ◽  
Power Station ◽  
Storage Unit ◽  
Pump Turbine ◽  
Pumped Storage ◽  
Primary Frequency

Pumped storage power station is an important regulating tool for peak load regulation and frequency regulation of the power grid, especially its primary frequency regulation function, which is of profound significance for the safety and stability of the power grid. As the core equipment of the pumped storage power station, the reversible design of the pump turbine makes it easy to have hydraulic fluctuation and mechanical instability when the unit runs to the “S” characteristic area, which will cause the frequency oscillation of the generator under the condition of primary frequency regulation. Therefore, some innovative work is studied in this paper: (1) an accurate hydraulic-mechanical-electrical coupling system mathematical model of pumped storage unit regulation system (PSURS) is established based on full characteristic curve of the pump turbine and seventh-order synchronous generator and excitation system; (2) the dynamic response characteristics of primary frequency regulation of pumped storage unit (PSU) under different water heads and different frequency disturbances are analyzed by numerical simulation; (3) in view of the unstable condition of the unit under the large frequency disturbance when it operates in the low head and small load area, the objective optimization function considering the ITAE index of hydraulic, mechanical, and electrical factors is proposed; and (4) fractional-order PID controller and the bacterial-foraging chemotaxis gravitational search algorithm (BCGSA) combined optimization strategy is used for PSURS optimization regulation and parameter optimization. The results show that the joint optimization strategy proposed in this paper has smaller objective function value, and makes the PSURS pass through the unbalanced area quickly, with better primary frequency regulation speed and smaller regulation depth.

scholarly journals Effect of Seal Locations of Pump-Turbine on Axial Hydraulic Trust

2021 ◽  
Vol 9 (6) ◽  
pp. 623
Author(s):  
Huifang Sun ◽  
Yue Lv ◽  
Jinbing Ni ◽  
Xianyu Jiang ◽  
Zhengwei Wang
Keyword(s):  
Great Influence ◽  
Load Condition ◽  
Central Axis ◽  
Operating Efficiency ◽  
Stable Operation ◽  
Pressure Balance ◽  
Power Station ◽  
Pump Turbine ◽  
Radial Dimension ◽  
Ring Seal

Axial hydraulic thrust is an important factor that affects safety and stability of pump turbine operation. Research and analysis of axial hydraulic thrust is of a great significance for guiding the safe and stable operation of a pumped storage power station. Since the runner shape of the pump turbine is flat and its radial dimension is large, an increase of leakage can happen easily. In order to reduce the leakage and improve the efficiency of the unit, a labyrinth ring seal is usually used in the upper crown and lower ring of the runner because the inner clearance of the seal has a great influence on the axial thrust. In order to study the influence of the change of labyrinth seal position on axial hydraulic thrust, a fluid domain model with a pressure balance pipe, upper crown clearance, and lower ring clearance is established for a pump turbine of a power station. The distribution position of labyrinth ring in the upper crown clearance is changed. The CFD numerical simulations are carried out under both 100% working load and 75% working load of turbine conditions, considering the flow in clearance areas. The research results of this paper have found that the axial hydraulic thrust of the 100% load condition is consistent with the change of the gap position compared with the 75% load condition. The amplitude of the change of the water thrust under the 100% load condition is greater. As the sealing position of the labyrinth ring in the upper crown gap moves away from the central axis, the resultant vertical and upward water thrust increases, and the operating efficiency of the unit first increases and then decreases. As the position of the labyrinth ring seal in the upper ring clearance moves away from the central axis, the resultant vertical and upward water thrust increases, and the operating efficiency of the unit first increases and then decreases. Defining the radial dimension ratio δ between the front clearance area and the total area of labyrinth ring, the closer δ is to 0.5, the unit efficiency is higher; the smaller that δ is, then the high pressure area in the upper crown clearance is smaller, and the hydraulic thrust force increases vertically. Considering a variety of factors, the clearance seal position has the optimal value. In the practical application of the project, the condition of excessive upward hydraulic thrust leading to the lifting of the unit can be avoided, and the phenomenon of excessive downward hydraulic thrust leading to the excessive load-bearing of the frame is evitable.

Mechanism and influence factors of hydraulic fluctuations in a pump-turbine

2021 ◽  
pp. 095765092110285
Author(s):  
Xiaolong Fu ◽  
Deyou Li ◽  
Hongjie Wang ◽  
Guanghui Zhang ◽  
Xianzhu Wei
Keyword(s):  
Guide Vane ◽  
Three Dimensional ◽  
Influence Factors ◽  
Simulation Method ◽  
Power Station ◽  
Pump Turbine ◽  
Available Energy ◽  
Exciting Forces ◽  
Pump Storage Power ◽  
Pumped Storage

Pumped-storage power technology is currently the only available energy storage technology in the grid net, and its reliability is receiving attention increasingly. However, when a pump-turbine unit undergoes runaway transitions, hydraulic fluctuations intensively affect the reliable operation of a pumped-storage power station. To reduce hydraulic fluctuations, this study investigated the formation mechanism of hydraulic fluctuations and explored its influence factors. In this study, a developed one-dimensional and three-dimensional (1 D-3D) coupling simulation method was adopted. Transient runaway transitions of a pump-turbine with three different inertias (0.5 J, 1 J, and 2.0 J) at three different guide vane openings (21°, 15°, and 12°, respectively) were simulated and compared. The results suggest that, at smaller guide vane openings (15° and 12°), water hammer owing to the increase in rotational speed is the primary unstable issue compared to the pulsation of radial hydraulic exciting forces on the runner. However, at a larger guide vane opening (21°), the latter owing to the back-flow near the runner inlet is the primary unstable issue. Moreover, it is found that a sufficiently large inertia improves the hydraulic fluctuations of the pump-storage power station, particularly in reducing the pulsation of radial hydraulic exciting loads on the runner. The findings of this study provide a valuable reference for determining suitable rotor inertia.

Experimental Study of Pressure Fluctuations of a Pump-Turbine in Transient Period

2012 ◽  
Vol 516-517 ◽  
pp. 896-899
Author(s):  
Yue Kun Sun ◽  
Zhi Gang Zuo ◽  
Shu Hong Liu ◽  
Jin Tao Liu ◽  
Yu Lin Wu
Keyword(s):  
Experimental Study ◽  
Turbine Unit ◽  
Pressure Fluctuations ◽  
Power Station ◽  
Operating Period ◽  
Pump Turbine ◽  
Guide Vanes ◽  
Transient Period ◽  
Rotor Stator Interaction ◽  
Pump Storage Power

Pressure fluctuations strongly affect the performance stability of the Pump-turbine unit. According to previous research, pressure fluctuations observed between runner and guide vanes (vaneless area) have the large amplitudes and complicated sources. This article analyzed this type of pressure fluctuations in transient operating period, by carrying out observations in a pump-storage power station. Amplitudes and frequencies were analyzed to show the characteristics of pressure fluctuations caused by rotor-stator interaction, vibration and vortex.

Effect of the Speed Factor On the Amplitude of the Blade Passing Frequency in the Vaneless Space of a Pump Turbine in Turbine Mode

2021 ◽  
Author(s):  
Jinhong Hu ◽  
Jiebin Yang ◽  
Wei Zeng ◽  
Jiandong Yang
Keyword(s):  
Strouhal Number ◽  
Goodness Of Fit ◽  
Guide Vane ◽  
Mathematical Relationship ◽  
Pump Turbine ◽  
Speed Factor ◽  
Blade Passing Frequency ◽  
Rotor Stator Interaction ◽  
Pumped Storage ◽  
Turbine Mode

Abstract An exponential expression describing the relationship between the amplitude of the blade passing frequency in the vaneless space of a pump turbine operating in the turbine mode and the speed factor is proposed based on statistical analysis. This mathematical relationship was discovered through signal processing of the data recorded during the emergency load rejection process of a prototype pump turbine. Subsequently, based on the pumped-storage test rig at Wuhan University, an experimental investigation was conducted to verify this mathematical relationship. The results indicated that, under the optimal guide vane opening of the model pump turbine, the goodness of fit of this mathematical relationship was quite high. As for the Francis pump turbine, the speed factor corresponds to the Strouhal number. Therefore, for this correlation, the underlying physical mechanism is the influence of the Strouhal number. This relation could inform the design and operation of pump turbines to control the intensity of pressure pulsations in the vaneless space. In addition, based on this mathematical relationship, the intensity of the rotor-stator interaction for different pump turbines can be compared quantitively.

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