Axial Force Analysis of the Support Bracket of Pumped Storage Unit

During operation, the support bracket is the main part to withstand the axial loads of the pumped storage unit. Moreover, the effects of axial loads including the hydraulic thrust of runner flow and the weight of runner body may cause the support bracket deformation and fatigue damage. For the safe and stable operation, the simulation of the axial force and the structural analysis of the support bracket of a pumped storage unit was carried out in this paper. The CFD simulation result has revealed the variation rule of the axial force in different operating conditions. Using ANSYS Mechanical, the static stresses and deformation of support bracket with axial loads were calculated. The results release the location and variations of maximum stress and maximum deformation caused by the axial loads. By comparing the predicted maximum axial force with the admission force calculated by the structural analysis, it is found that the axial force of the researched machine is within the safe range. This study provides the reference for the safety and stable operation of the pumped storage unit.

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Nonlinear Modeling of Dynamic Characteristics of Pump-Turbine

Energies ◽

10.3390/en15010297 ◽

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.

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Fixed-speed and Variable-speed Pumped Storage Dispatch Model in Power Systems with High Renewable Penetration

E3S Web of Conferences ◽

10.1051/e3sconf/20183804014 ◽

2018 ◽

Vol 38 ◽

pp. 04014

Author(s):

Bo Yuan ◽

Jin Zong ◽

Zhicheng Xu

Keyword(s):

Power Systems ◽

Linear Optimization ◽

Operating Conditions ◽

Economic Life ◽

Mixed Integer ◽

Variable Speed ◽

Operating Characteristics ◽

Storage Unit ◽

New Energy ◽

Pumped Storage

According to different operating characteristics of pumped storage fixed speed unit and variable speed unit, a joint dispatching model of pumped storage unit and other types of units based on mixed integer linear optimization is constructed. The model takes into account the operating conditions, reservoir capacity, cycle type and other pumped storage unit constraints, but also consider the frequent start and stop and the stability of the operation of the unit caused by the loss. Using the Cplex solver to solve the model, the empirical example of the provincial power grid shows that the model can effectively arrange the pumping storage speed and the dispatching operation of the variable speed unit under the precondition of economic life of the unit, and give full play to the function of peak shaving and accommodating new energy. Because of its more flexible regulation characteristics of power generation and pumping conditions, the variable speed unit can better improve the operating conditions of other units in the system and promote the new energy dissipation.

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Transient thermo-elasto-hydrodynamic analysis of a bidirectional thrust bearing in start-up and shutdown processes

Engineering Computations ◽

10.1108/ec-03-2021-0128 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Jingwei Cao ◽

Liming Zhai ◽

Yongyao Luo ◽

Soo-Hwang Ahn ◽

Zhengwei Wang ◽

...

Keyword(s):

Thrust Bearing ◽

Stable Operation ◽

Thermal Interaction ◽

Lubrication Mechanism ◽

Interaction Method ◽

Storage Unit ◽

Content Type ◽

Start Up ◽

Lubrication Characteristics ◽

Pumped Storage

PurposeThe purpose of this paper is to reveal the transient thermo-elasto-hydrodynamic lubrication mechanism of a bidirectional thrust bearing in a pumped-storage unit, and to propose the transient simulation method of two-way fluid-solid-thermal interaction of thrust bearing.Design/methodology/approachThe transient fluid-solid-thermal interaction method is used to simulate the three-dimensional lubrication of the thrust bearing, during the start-up and shutdown process of a pumped storage unit. A pad including an oil hole is modelled to analyze the temporal variation of lubrication characteristics, such as the film pressure, thickness and temperature, during the transient operation process.FindingsThe injection of the high-pressure oil sufficiently affects the lubrication characteristics on film, in which the hysteresis phenomena were found between the start-up and shutdown possess.Originality/valueThis paper reveals the transient lubrication mechanism of tilting pad in a thrust bearing, by means of transient fluid-solid-thermal interaction method. Lubrication characteristics are simulated without assuming the temperature relationship between the oil film inlet and the outlet and the heat transfer on the pad free surface. This paper provides a theoretical basis for the safe design and stable operation of thrust bearings.

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Control of the Variable-Speed Pumped Storage Unit-Wind Integrated System

Mathematical Problems in Engineering ◽

10.1155/2020/3816752 ◽

2020 ◽

Vol 2020 ◽

pp. 1-9

Author(s):

Yifeng Shi ◽

Xiangjian Shi ◽

Chuanbao Yi ◽

Xufeng Song ◽

Xiaogang Chen

Keyword(s):

Wind Power ◽

Power Flow ◽

Significant Contribution ◽

Control Method ◽

Integrated System ◽

Stable Operation ◽

Variable Speed ◽

Storage Unit ◽

Active Power Flow ◽

Pumped Storage

The integration of variable-speed pumped storage unit (VS-PSU) guarantees an efficient peak regulation and frequency modulation of the power grid. The present research analyzes the active power flow of the VS-PSU under synchronous, subsynchronous, and supersynchronous speed in both generation and pumping modes. The control strategy of the VS-PSU is realized by the dq-axis vector control method. Furthermore, the control of the VS-PSU integrated with wind power has been conducted using DIgSILENT platform with the VS-PSU of 300 kW capacity. Results show that the fluctuation of the power output of the wind power plant can be reduced effectively. The safe, economical, and stable operation of power system integrated with wind power can be achieved by the significant contribution of the VS-PSU.

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Degradation Trend Prediction of Pumped Storage Unit Based on MIC-LGBM and VMD-GRU Combined Model

Energies ◽

10.3390/en15020605 ◽

2022 ◽

Vol 15 (2) ◽

pp. 605

Author(s):

Peng Chen ◽

Yumin Deng ◽

Xuegui Zhang ◽

Li Ma ◽

Yaoliang Yan ◽

...

Keyword(s):

Performance Degradation ◽

Operating Conditions ◽

Gradient Boosting ◽

Degradation Index ◽

Trend Prediction ◽

Storage Unit ◽

Light Gradient ◽

Proposed Model ◽

Pumped Storage ◽

Maximal Information Coefficient

The harsh operating environment aggravates the degradation of pumped storage units (PSUs). Degradation trend prediction (DTP) provides important support for the condition-based maintenance of PSUs. However, the complexity of the performance degradation index (PDI) sequence poses a severe challenge of the reliability of DTP. Additionally, the accuracy of healthy model is often ignored, resulting in an unconvincing PDI. To solve these problems, a combined DTP model that integrates the maximal information coefficient (MIC), light gradient boosting machine (LGBM), variational mode decomposition (VMD) and gated recurrent unit (GRU) is proposed. Firstly, MIC-LGBM is utilized to generate a high-precision healthy model. MIC is applied to select the working parameters with the most relevance, then the LGBM is utilized to construct the healthy model. Afterwards, a performance degradation index (PDI) is generated based on the LGBM healthy model and monitoring data. Finally, the VMD-GRU prediction model is designed to achieve precise DTP under the complex PDI sequence. The proposed model is verified by applying it to a PSU located in Zhejiang province, China. The results reveal that the proposed model achieves the highest precision healthy model and the best prediction performance compared with other comparative models. The absolute average (|AVG|) and standard deviation (STD) of fitting errors are reduced to 0.0275 and 0.9245, and the RMSE, MAE, and R2 are 0.00395, 0.0032, and 0.9226 respectively, on average for two operating conditions.

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TEHD analysis of a bidirectional thrust bearing in a pumped storage unit

Industrial Lubrication and Tribology ◽

10.1108/ilt-07-2015-0092 ◽

2016 ◽

Vol 68 (3) ◽

pp. 315-324 ◽

Cited By ~ 3

Author(s):

Liming Zhai ◽

Zhengwei Wang ◽

Yongyao Luo ◽

Zhongjie Li

Keyword(s):

Thrust Bearing ◽

Three Dimensional ◽

Elastic Equilibrium ◽

Operating Conditions ◽

Storage Unit ◽

Content Type ◽

Thrust Bearings ◽

Tilting Pad ◽

Lubrication Characteristics ◽

Pumped Storage

Purpose The purpose of this paper is to analyze lubrication characteristics of a bidirectional thrust bearing in a pumped storage, considering the effect of the thermal elastic deformation of the pad and collar. Design/methodology/approach This study used the fluid–solid interaction (FSI) technique to investigate the lubrication characteristics of a bidirectional thrust bearing for several typical operating conditions. The influences of the operating conditions and the thrust load on the lubrication characteristics were analyzed. Then, various pivot eccentricities were investigated to analyze the effects of the pivot position. Findings It is found that the effect of the radial tilt angle of the collar runner on the oil film is compensated for by the radial tilt of the pad. The central pivot support system is the main factor limiting the loads of bidirectional thrust bearings. Originality/value This paper has preliminarily revealed the lubrication mechanism of bidirectional tilting-pad thrust bearings. A three-dimensional FSI method is suggested to evaluate the thermal–elastic–hydrodynamic deformations of thrust bearings instead of the conventional method, which iteratively solves the Reynolds equation, the energy equation, the heat conduction equation and the elastic equilibrium equation.

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

Water Practice & Technology ◽

10.2166/wpt.2015.026 ◽

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.

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Research and Develop on Static Frequency Converter of Pumped Storage Power Plant

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.608-609.1120 ◽

2012 ◽

Vol 608-609 ◽

pp. 1120-1126 ◽

Cited By ~ 1

Author(s):

De Shun Wang ◽

Bo Yang ◽

Lian Tao Ji

Keyword(s):

Power Plant ◽

Control Strategy ◽

Large Scale ◽

Frequency Converter ◽

Position Estimation ◽

Position Sensor ◽

Storage Unit ◽

Rotor Position ◽

Start Up ◽

Pumped Storage

A static frequency converter start-up control strategy for pumped-storage power unit is presented. And rotor position detecting without position sensor is realized according to voltage and magnetism equations of ideal synchronous motor mathematics model. The mechanism and implementation method of initial rotor position determination and rotor position estimation under low frequency without position sensor are expounded and validated by simulations. Based on the mentioned control strategy, first set of a static frequency converter start-up device in China for large-scale pumped-storage unit is developed, which is applied to start-up control test in the 90 MW generator/motor of Panjiakou Pumped-storage Power Plant. Test results show that rotor position detecting, pulse commutation, natural commutation, and unit synchronous procedure control of static start-up are all proved. The outcomes have been applied in running equipment, which proves the feasibility of mentioned method.

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