Advance in Research on Air Cushion Surge Chamber in Hydropower Plant

2007 ◽  
Author(s):  
Jianyong Hu ◽  
Jian Zhang ◽  
Lisheng Suo ◽  
Jie Fang
Keyword(s):  
Engineering Geology ◽  
Water Hammer ◽  
Hydropower Plant ◽  
Control Mode ◽  
Normal Operation ◽  
Air Leakage ◽  
Surge Tank ◽  
Key Factor ◽  
Air Cushion ◽  
Operation Control

Air cushion surge chamber is an important measure of water hammer protection in hydropower plant. Compared with conventional surge tank, air cushion surge chamber is more efficient to decrease the water hammer pressure and improve operating condition of turbine and is more economic. At the same time, because it is often constructed in the ground, it destroyed the natural environment slightly less than conventional surge tank. Condition of engineering geology is a key factor if air cushion surge chamber will be applied. Quantity of air leakage is directly relative to the normal operation of air surge chamber. Appropriate design of operation control mode is also important to the safety of hydropower plant. In this paper, principle and application of air cushion surge chamber in hydropower plant are introduced briefly; the main engineering problems are presented; achievements of research are summarized and analyzed including engineering geology, air characteristics, prediction and control of air leakage, hydraulic performance and operation control. Finally, problems that need to be research in the future and prospective applications are provided.

Reliable Analysis on Fast Valving of Ultra-Supercritical Unit Under Transient Fault Conditions

2017 ◽  
Author(s):  
Yu Cai ◽  
Wei Li ◽  
Bao Zhang ◽  
Wenjian Wu ◽  
Deren Sheng ◽  
...  
Keyword(s):  
Power System ◽  
Steam Turbine ◽  
Dynamic Model ◽  
Transient Stability ◽  
Power Grid ◽  
Load Shedding ◽  
Control Mode ◽  
Normal Operation ◽  
Transient Fault ◽  
The Stability

Fast valving of ultra-supercritical unit has great effects on over-speed prevention, load-shedding control, transient stability analysis of electrical system and other security problems. The purpose of fast valving is to maintain the stability of power system once fault or load shedding of unit occurs in the electric power system. Therefore, it is of great significance to study the reliability of fast valving for ultra-supercritical unit. In this paper, the KU ( short shedding) logic condition of SIEMENS T3000 system is analyzed as the research object of fast valving. The unit can be avoided over speed by monitoring the unit load and fast valving under faulty grid conditions based on the KU control. A series of measures will be taken after KU is triggered, for instance the governing valving will be closed quickly and the DEH (digital electro-hydraulic) control of the steam turbine will be switched to speeding control mode. On the other hand, the unit will return to normal operation if the transient fault of power grid disappears. The key contributions of this thesis include three parts: Firstly, based on the analysis of control characteristics of ultra-supercritical unit and protective logic and triggered conditions of KU function, a novel dynamic model by coupling the fast valving of steam turbine and the transient stability of generator is established by applying the PSCAD software. Then, the dynamic response process of ultra-supercritical unit is simulated and calculated by adopting the coupling dynamic model when KU function is triggered. Also the influence factors and reliability of fast valving are analyzed under transient fault conditions. Finally, two optimized measures by increasing the time delay and the speed of quantitative judgment are put forward to reduce risks and avoid the misoperation of signal distortion which may be caused by the power transmitter under transient fault conditions. The results of this study can not only help to evaluate the reliability of fast valving function scientifically in power grid transient fault, but also guide the technicians to analyze the stability of the power grid.

scholarly journals Water Hammer Control Analysis of an Intelligent Surge Tank with Spring Self-Adaptive Auxiliary Control System

Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2527 ◽  
Author(s):  
Wuyi Wan ◽  
Boran Zhang ◽  
Xiaoyi Chen ◽  
Jijian Lian
Keyword(s):  
Control Function ◽  
Water Hammer ◽  
Control Device ◽  
Control Analysis ◽  
Surge Tank ◽  
Transient Pressure ◽  
Supply Pipe ◽  
Proposed Model ◽  
Vertical Size ◽  
Self Adaptive

The water hammer can cause great risks in water supply pipe systems. A surge tank is a kind of general water hammer control device. In order to improve the behavior of the surge tank, a self-adaptive auxiliary control (SAC) system was proposed in this paper. The system can optimize the response of the surge tank according to the transient pressure. The numerical model and the matched boundary conditions were established to simulate the improved surge tank and optimize the SAC system. Then, various transient responses were simulated by the proposed model with different parameters set. The proposed system is validated by comparing the water hammer process in a river-pipe-valve (RLV) system with and without SAC. The results show that the SAC can greatly improve the water hammer control of the pipeline and the water level oscillation of the surge tank. With the SAC system, the required vertical size of the surge tank can be significantly reduced with the desired water hammer control function.

Optimal Control Mode of the Vakhsh Hydropower Reservoirs to Reduce Electricity Shortages in Tajikistan

2015 ◽  
Vol 792 ◽  
pp. 446-450 ◽  
Author(s):  
Yuri Sekretarev ◽  
Sherkhon Sultonov ◽  
Victor Shalnev
Keyword(s):  
Power Generation ◽  
Optimal Control ◽  
Hydropower Plant ◽  
Control Mode ◽  
Modes Of Operation ◽  
Hydropower Plants ◽  
Hydropower Reservoirs

The paper is aimed to determine runoff limits of the Vakhsh cascade hydropower plant, which are the main parameters when setting optimum modes of the hydropower plant. It is proposed to increase power generation of the hydropower plant of the Vakhsh cascade by assigning the optimal modes of operation of hydropower plants. The peculiarities of managing the cascades of hydropower plants are described. The description of the Vakhsh cascade hydropower plant and the method of controlling the reservoir of the cascade of the hydropower plants are given.

Research on Impact and Solutions of Voltage Stability of Distributed Wind Power Integration

2014 ◽  
Vol 953-954 ◽  
pp. 365-368
Author(s):  
Guang Lei Li ◽  
Zhao Xin Wang ◽  
Hua Deng ◽  
Yu Jia Wang ◽  
Tao Chen
Keyword(s):  
Wind Power ◽  
Large Scale ◽  
Voltage Stability ◽  
Control Mode ◽  
Engineering Practice ◽  
Technology Research ◽  
Wind Power Integration ◽  
Practice Experience ◽  
Resource Type ◽  
Operation Control

Aiming at the problem of lack of engineering practice experience and corresponding technology research, this paper reveal the interactive mechanism of distributed wind power and power grid. Based on the actual network frame and planning network frame, this paper establish analysis database, analyze problem of voltage stability by large amount of wind power integration into power system, propose the adjustment measures of voltage, put forward operation control mode of distributed wind. These can be used to guide the large-scale development of distributed wind power, which makes the development of distributed wind power guided by resource type of guiding transition to grid type.

Transient Pressure Analysis of a Prototype Pump Turbine: Field Tests and Simulation

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Jinhong Hu ◽  
Jiandong Yang ◽  
Wei Zeng ◽  
Jiebin Yang
Keyword(s):  
Field Tests ◽  
Water Hammer ◽  
Hydropower Plant ◽  
Pressure Pulsations ◽  
Transient Pressure ◽  
Pump Turbine ◽  
Operation Conditions ◽  
Spiral Case ◽  
Transient Events ◽  
Transient Variations

The transient behaviors of a prototype pump turbine are very important to the safe operation of a pumped-storage power plant. This is because the water hammer pressure during transient events affects the pressure surges in the spiral case (SC) and the draft tube (DT). In addition, the transient pressure pulsations in the vaneless space (VL) are important in the evaluation of the life of the runner. Although several detailed studies have been conducted on the water hammer pressure of a hydropower plant, very few have considered the transient pressure pulsations that occur in the pump turbine. The objective of the present study was to determine the characteristics of the transient pressure pulsations of a 300-MW prototype Francis pump turbine during load rejection and power failure. For this purpose, the frequency features in the steady-state were first analyzed using fast Fourier transform. A Savitzky–Golay filter was then used to extract the water hammer pressure and pulsating pressure from the acquired raw pressure signals. Further, a one-dimensional (1D) method of characteristics (MOC) mathematical model of the pump-turbine was established and used to simulate the transient variations of the flow discharge during transient events, to enable the division of the transient operation conditions into several domains. Finally, the characteristics of the transient pressure pulsations in the SC, vaneless space, and DT were investigated in the time and frequency domains. This paper also discusses the causes of the pressure pulsations that occur under different modes of operation of a pump turbine.

scholarly journals Energy production assessment in a complex hydropower development

2019 ◽  
Vol 22 (4) ◽  
pp. 725-737 ◽  
Author(s):  
Andrei-Mugur Georgescu ◽  
Sanda-Carmen Georgescu ◽  
Georgiana Dunca ◽  
Diana Maria Bucur ◽  
Alexandru Aldea
Keyword(s):  
Numerical Model ◽  
Energy Production ◽  
Point Of View ◽  
Hydropower Plant ◽  
Normal Operation ◽  
Centrifugal Pumps ◽  
Hydropower Development ◽  
Upstream Reservoir ◽  
Set Up ◽  
Pumped Storage

Abstract A complex multi-reservoir hydropower development (HPD) was studied from the point of view of energy production. The Gâlceag HPD system consists of three reservoirs, a high head hydropower plant (HPP) powered by two Francis turbines of 75 MW each, and a pumping station (PS) equipped with two centrifugal pumps of 10 MW each. The hydraulic system configuration is unusual: the PS discharge pipe conveys the water directly into HPP's penstock. Three operation scenarios were investigated: ① normal operation (with PS shutdown and HPP operational, as a conventional HPP), ② simultaneous operation (with both HPP and PS operational), and ③ pumped storage (with HPP shutdown and PS operational). Primarily, a numerical model was set up in EPANET to investigate the influence that the variation in the initial level of the HPP upstream reservoir has on the production of energy. In the sequel, a numerical model was derived and solved in GNU Octave to investigate the influence on the energy production of HPD due to initial levels of both the HPP upstream and downstream reservoirs. The results can be used in a decision support system to assess the overall operation of Gâlceag HPD based on water availability.

scholarly journals Investigation of an Air-Cushion Supported Solar Island

2018 ◽  
Author(s):  
Trygve Kristiansen ◽  
Petter Borvik
Keyword(s):  
Failure Modes ◽  
Preliminary Investigation ◽  
Circular Cross Section ◽  
Linear Potential ◽  
Air Leakage ◽  
General Behaviour ◽  
Supported Membrane ◽  
Flexible Mode ◽  
Air Cushion ◽  
Wave Conditions

A preliminary investigation of a low-weight carrying marine platform concept was conducted by means of experiments and approximate theories. The platform consists of a circular elastic tube with circular cross-section, covered with an air-supported membrane deck. A vertical skirt is added along the circumference of the model to avoid air-leakage. We refer to this concept as floating solar island. Solar islands have recently gained interest. The models were subjected to waves. Both regular and irregular wave tests were conducted. Tests with the absence of the membrane (floater only) were also conducted. The general behaviour and failure modes were investigated. Failure modes include over-topping with flooding as consequence, as well as out-of-water incidents and membrane wear with air leakage as consequence. A systematic variation of wave conditions revealed for which wave conditions flooding occured. Out-of-water incidents of the skirt were not observed. Vertical accelerations were measured at eight positions along the circumference of the model, and the heave, pitch and first flexible mode motions were re-constructed by modal theory. The modal responses were compared to theory based on linear potential flow assumption, both for the floater model only, and with simplified theory accounting for the air-cushion of the island in heave. The theory was able to predict the global behaviour reasonably well, although important discrepancies were observed. More detailed studies, involving experiments with more instrumentation and development of theory, must be conducted in case deeper understanding of this relatively complex, hydro-elastic concept is needed.

scholarly journals Water Hammer Stability in a Hydroelectric Plant with Surge Tank and Throttling

2019 ◽  
Vol 52 (18) ◽  
pp. 144-149 ◽  
Author(s):  
Daniela Danciu ◽  
Dan Popescu ◽  
Vladimir Răsvan
Keyword(s):  
Hydroelectric Plant ◽  
Water Hammer ◽  
Surge Tank
Sign in / Sign up

Export Citation Format

Share Document