Study on the Reversible Pump-Turbine Closing Law and Field Test

2006 ◽  
Author(s):  
Jian Zhang ◽  
Jianyong Hu ◽  
Ming Hu ◽  
Jie Fang ◽  
Ning Chen
Keyword(s):  
Field Test ◽  
Turning Point ◽  
Large Range ◽  
Rotation Speed ◽  
Sudden Change ◽  
Pressure Rise ◽  
Pump Turbine ◽  
Water Conveyance ◽  
Three Stages ◽  
Pumped Storage

In the operation of pumped storage plant, the sudden change of load in the large range often happen, the design of reversible pump-turbine emergency closing law should satisfy limit of rotation speed-rise and pressure-rise. The broken-line closing law of reversible pump-turbine usually used in pumped storage plants is discussed and based on full hydraulic characteristic of reversible pump-turbine, the broken-line closing law of three stages with delayed segment is designed, virtues and defects of the pump-turbine emergency closing law are also analyzed. Numerical calculation and field test indicate that water hammer in pumped storage plant water conveyance system caused by wicket gate closing together with rotation speed-rise, is effectively reduced by the closing laws presented above, especially to the latter, its turning point position can change following the different operating case, the detection of poor robustness is overcome. A new idea for the design of the reversible pump-turbine emergency closing law is proposed with good prospects.

Study on Field Test and Simulating Calculation Following Load Rejections of Tongbai Pumped Storage Power Station

2008 ◽  
Author(s):  
Jian Zhang ◽  
Delou Wang ◽  
Jianyong Hu ◽  
Jie Zhou ◽  
Jie Fang
Keyword(s):  
Field Test ◽  
Rotation Speed ◽  
Identical Result ◽  
Power Station ◽  
Pipe System ◽  
Simulating Calculation ◽  
Water Conveyance ◽  
Pumped Storage ◽  
Station Safety ◽  
Power Station Safety

Tongbai pumped storage plant of China have four sets of pump-turbines with single unit capacity 300MW, and the whole length of conveyance system about 1120m in which the lengths of diversion system and tailrace are about 748m and 347m respectively, rated head and discharge 244.0m and 143.5m3/s, separately. The plant would have the field test before the units were put into operating to ensure safety in future, and the parameters of pump turbines and water conveyance pipe system of pumped storage power station are rectified according to field test datum. Numerical calculation and field test indicate that water hammer in pumped storage plant water conveyance system caused by wicket gate closing together with rotation speed-rise. Compared with field test data following load rejection of two sets of pump turbines on June 30th, 2006, simulating calculation has identical result, which would ensure Tongbai pumped storage power station safety.

Application of Pressure Regulating Valve in the Hydraulic Transients of Hydropower Plant

2008 ◽  
Author(s):  
Jian Zhang ◽  
Shibo Ma ◽  
Jianyong Hu ◽  
Xiaodong Yu ◽  
Fulin Cai
Keyword(s):  
Guide Vane ◽  
Sudden Change ◽  
Pressure Rise ◽  
Hydropower Plant ◽  
Hydropower Station ◽  
Hydraulic Transients ◽  
Effective Measure ◽  
Spiral Case ◽  
Water Conveyance ◽  
Turbine Guide Vane

In the operation of the hydropower station, the sudden change of load in the large range often happen, the emergency closing law of turbine guide vane is difficult to control speed-rise and pressure-rise to the extent permitted for the length of pressure pipeline longer and discharge larger. With the development of the surge chamber of alternative technique, the pressure regulating valve is used to reduce the large pressure and speed-rise of the unit in hydraulic transients as the effective measure to saving investments. The layout of water conveyance system and process of hydraulic transients of a certain hydropower in China are analyzed, and the pressure regulating valve is installed in the spiral case inlet to meet the hydraulic regulation calculation guarantee after technical and economic comparison, for the joint action of valve and turbine guide vane, the pipeline water hammer pressure and unit speed-rise are reduced effectively. The pressure regulating valve diameter and opening and closing law in combination with the turbine guide vane are discussed in the power station, as well as the possible problems may be caused by the using of the pressure regulating valve is pointed out in theory. The achievements to scheme decision of adopting the pressure regulating valve to replace the surge chamber in high-head hydropower station with longer pressure water conveyance system can be for reference and provide the certain technological supply.

Load Rejection Test and Numerical Prediction of Critical Load Case Scenarios for Pumped Storage Plant

2017 ◽  
Author(s):  
Sheng Chen ◽  
Jian Zhang ◽  
Gaohui Li ◽  
Xiaodong Yu
Keyword(s):  
Critical Load ◽  
Field Test ◽  
Large Scale ◽  
Extreme Values ◽  
Numerical Prediction ◽  
Operating Conditions ◽  
Load Case ◽  
Pressure Pulsations ◽  
Water Conveyance ◽  
Pumped Storage

A pumped storage plant (PSP) is by far the most cost effective and mature technology for energy storage at a large-scale, and therefore, this technology is rapidly being developed and deployed. A reversible pump turbine (RPT) is the vital component of a PSP, and whether a PSP can operate safely and stably mainly depends on the characteristics of the RPT. However, the existence of S-shaped characteristics of a RPT usually leads to severe water hammer and pressure pulsations during the transient processes of load rejection. Therefore, hydraulic transient analysis in a PSP is one of the most important issues for the prevention of undesirable pressure fluctuations in waterways. Theoretically, the most accurate method is to conduct on-site measurements of all possible load cases to obtain the extreme values of pressure. However, extreme operating conditions such as 2-stage load rejection pose serious threats to the safety of the water conveyance system, making it impossible to carry out field trials under such conditions. This paper gives the numerical prediction of extreme and critical load case scenarios from the simultaneous load rejection field test on a double unit of a PSP in China. The dynamic transient numerical model for load rejection of the PSP is developed by introducing the method of characteristics. The boundary conditions, such as the real adopted wicket gate closure law and parameters of the water conveyance system, are calibrated according to the field test data. Considering the large pressure pulsations in the PSP during load rejection, a proper pressure pulsations amendment is proposed as well. Eventually, the hydraulic behavior of the critical load cases are numerically investigated by the modified model. And the results are amended by the proposed pressure pulsations processing approach to predict whether the hydraulic parameters can satisfy the design criteria, which can ensure safe operation of the PSP in the future. The achievements of the study can serve as a reference for similar PSP projects.

Study on the Hydraulic Transients of Pump-Turbines Load Successive Rejection in Pumped Storage Plant

2007 ◽  
Author(s):  
Jian Zhang ◽  
Weihua Lu ◽  
Jianyong Hu ◽  
Boqin Fan
Keyword(s):  
Draft Tube ◽  
Maximum Pressure ◽  
Hydraulic Transients ◽  
Pump Turbine ◽  
Hydraulic Unit ◽  
Interval Time ◽  
Minimum Pressure ◽  
Practical Operation ◽  
Water Conveyance ◽  
Pumped Storage

During the calculation of hydraulic transients in pumped storage plants, the speed change of reversible pump-turbine has great relation with the pressure of water conveyance system, and results in the minimum pressure at draft tube does not occur while all sets in the same hydraulic unit reject load simultaneously, but occurs in the combined conditions of load successive rejection. Based on the hydraulic characteristic of reversible pump-turbine, the reason why the minimum pressure at draft tube occur in the combined conditions and the dangerous interval time are analyzed bonding with the water conveyance system layout of pumped storage plants and the practical operation of pump-turbine. The research indicate that when reversible turbines in the same hydraulic unit reject load successively, the maximum pressure at spiral case maybe lower to some extent compared with load rejections simultaneously, but the change of minimum pressure drop at draft tube is great along with different interval time, which endangers the water conveyance system badly, especially in high head pumped storage plants, and should be pay great attention to it. Combining the practical operation of pump-turbine with calculation in theory, it would be the dangerous interval time of load successive rejection of pump-turbines after the first pump-turbine rejects load and its runaway speed achieve speed peak, the pressure of draft tube would drop the minimum once the other set in the same hydraulic unit also reject load at the moment.

Investigations on Aerodynamic Loading Limits of Subsonic Compressor Tandem Cascades: Midspan Flow

2013 ◽  
Author(s):  
Charlotte Hertel ◽  
Christoph Bode ◽  
Dragan Kožulović ◽  
Tim Schneider
Keyword(s):  
Mach Number ◽  
Wind Tunnel ◽  
Numerical Simulations ◽  
Pressure Distribution ◽  
Large Range ◽  
Pressure Rise ◽  
Transition Model ◽  
Diffusion Factor ◽  
Aerodynamic Loading ◽  
Tandem Cascades

An optimized subsonic compressor tandem cascade was investigated experimentally and numerically. Since the design aims at incompressible applications, a low inlet Mach number of 0.175 was used. The experiments were carried out at the low speed cascade wind tunnel at the Technische Universität Braunschweig. For the numerical simulations, the CFD-solver TRACE of DLR Cologne was used, together with a curvature corrected k-ω turbulence model and the γ-Reθ transition model. Besides the incidence variation, the aerodynamic loading has also been varied by contracting endwalls. Results are presented and discussed for different inlet angles and endwall contractions: pressure distribution, loss coefficient, turning, pressure rise, AVDR and Mach number. The comparison of experimental and numerical results is always adequate for a large range of incidence. In addition, a comparison is made to an existing high subsonic tandem cascade and conventional cascades. For the latter the Lieblein diffusion factor has been employed as a measure of aerodynamic loading to complete the Lieblein Chart of McGlumphy [1].

scholarly journals Pressure Analysis in the Draft Tube of a Pump-Turbine under Steady and Transient Conditions

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4732
Author(s):  
Jing Yang ◽  
Yue Lv ◽  
Dianhai Liu ◽  
Zhengwei Wang
Keyword(s):  
Steady State ◽  
Pressure Pulsation ◽  
Transient Flow ◽  
Draft Tube ◽  
Simulation Method ◽  
Wall Pressure ◽  
Pump Turbine ◽  
Steady State Condition ◽  
Transient Conditions ◽  
Pumped Storage

Pumped-storage power stations play a regulatory role in the power grid through frequent transition processes. The pressure pulsation in the draft tube of the pump-turbine under transient processes is important for safe operation, which is more intense than that in the steady-state condition. However, there is no effective method to obtain the exact pressure in the draft tube in the transient flow field. In this paper, the pressure in the draft tube of a pump-turbine under steady-state and transient conditions are studied by means of CFD. The reliability of the simulation method is verified by comparing the real pressure pulsation data with the test results. Due to the distribution of the pressure pulsation in the draft tube being complex and uneven, the location of the pressure monitoring points directly affects the accurate judgement of cavitation. Eight monitoring surfaces were set in the straight cone of the draft tube and nine monitoring points were set on each monitoring surface to analyze the pressure differences on the wall and inside the center of the draft tube. The relationships between the pressure pulsation value inside the center of the draft tube and on the wall are studied. The “critical” wall pressure pulsation value when cavitation occurs is obtained. This study provides references for judging cavitation occurrences by using the wall pressure pulsation value in practical engineering.

Study on Engineering Mechanical Properties of Mayanpo Slope at Xiangjiaba Hydropower Station

2012 ◽  
Vol 548 ◽  
pp. 511-515
Author(s):  
Jian Hui Sun ◽  
Long Jiang ◽  
Wan Shun Wang ◽  
Chen Lin Xiong ◽  
Zhao Hui Zhu
Keyword(s):  
Mechanical Properties ◽  
Field Test ◽  
Dynamic Equilibrium ◽  
Three Dimensional ◽  
Strength Reduction ◽  
Hydropower Station ◽  
Weak Interlayer ◽  
Internal Deformation ◽  
Three Stages ◽  
Changing Rate

Through the field test of Mayanpo slope at Xiangjiaba Hydropower Station, external deformation, deep deformation, groundwater level and stability of the slope with weak interlayer are analyzed in this paper. The results show that: ① displacement deformation increases with time and decreases with increasing depth. Changes of displacement can be divided into three stages: deformation rapidly increases in the early, and slowly increases in the medium, and becomes gradually stable in the later. Changing rate of displacement decreases with time, and the rate can also be divided into three stages, basically consistent with the displacement changing stage; ② a certain thickness of weak interlayer and evident dislocation exists in slope strata. Dislocation rate first increases and then decreases until basically stable, and local fluctuation is mainly affected by rainfall and dynamic equilibrium adjustment of the slope internal deformation; ③based on the penalty function contact of pile soil and the surface of rock mass, the three-dimensional numerical model of coupling of seepage and strain has been established, and through analyzing and comparing with field test data, it is verified that the model is feasible in the study on slope deformation; ④ through stability analysis of Mayanpo slope by strength reduction FEM, stability coefficient is 1.72.

Rheological Characteristics of Residue Binder from Low Penetration Grade Bitumen Emulsion

2012 ◽  
Vol 509 ◽  
pp. 328-332 ◽  
Author(s):  
Guang Ji Xu ◽  
Mei Zhu Chen ◽  
Shao Peng Wu ◽  
Martin Van de Ven ◽  
Steven Mookhoek
Keyword(s):  
Phase Angle ◽  
Large Range ◽  
Complex Modulus ◽  
Rheological Characteristics ◽  
Curing Process ◽  
Master Curves ◽  
Recovery Method ◽  
Stabilization Process ◽  
Bitumen Emulsion ◽  
Three Stages

In this study, residue binders from low penetration grade bitumen emulsions were investigated on the basis of rheology and were compared to the neat bitumen binders of which they were produced. The recovery method proposed by EN 13074 (including both recovery and stabilization process at moderate temperatures) was selected to obtain the residue binders used in the analysis, and the corresponding neat binders were treated the same for comparison. The rheological properties of residue binder from low penetration grade bitumen emulsion were evaluated using Dynamic Shear Rheometer (DSR). During the curing process, three stages were divided, and master curves of complex modulus and phase angle were constructed to allow comparison of the residue binder over a large range of frequencies for each stage. The results showed that the complex modulus increases while the phase angle decreases with curing process for the residues, indicating a better performance in terms of elasticity and stiffness.

Field Test and Analysis of Swelling Force under Atmosphere Action

2012 ◽  
Vol 450-451 ◽  
pp. 1415-1418
Author(s):  
Xiong Wei Li ◽  
Yong Wang ◽  
Yong Zhang
Keyword(s):  
Engineering Design ◽  
Field Test ◽  
Sudden Change ◽  
Expansive Soil ◽  
Rain Season

Considering the influence of atmosphere action, field test of swelling force on expansive soil is carried out in Nanning Guangxi. The test sustains a whole rain season. The testing results show that swelling force is closely linked to the process of rainfall. The phenomenon, that long drought turns the rain, induces a sudden change of swelling force. But the persistence of rainfall brings different influence on vertical and horizontal swelling force. The results of field test can provide reference to optimize the engineering design.

Experiences on Startup and Trial Operation at Yards Creek Pumped Storage Project

1969 ◽  
Vol 91 (3) ◽  
pp. 387-395 ◽  
Author(s):  
R. J. Swed ◽  
K. H. Yang
Keyword(s):  
Pump Turbine ◽  
Exchange Of Information ◽  
Pumped Storage

Many problems were encountered during the startup and trial operation at Yards Creek. This paper describes the major problems and how they were resolved. There are many questions about pump-turbine operation that remain unanswered. Exchange of information and experience is needed. The authors hope that this article will help to stimulate this exchange of information.

Sign in / Sign up

Export Citation Format

Share Document