scholarly journals Dynamic Safety Assessment in Nonlinear Hydropower Generation Systems

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Shuang Li ◽  
Yong Yang ◽  
Qing Xia
Keyword(s):  
Transient Process ◽  
Safety Assessment ◽  
Hydropower Station ◽  
Generation System ◽  
Hydropower Generation ◽  
Safety Level ◽  
Fisher Discriminant ◽  
The Stability ◽  
Evolution Behavior ◽  
Hydropower Stations

This paper focuses on the stability problems in a hydropower station. To enable this study, we consider a nonlinear hydropower generation system for the load rejection transient process based on an existing hydropower station. Herein we identify four critical variables of the generation system. Then, we carry out the dynamic safety assessment based on the Fisher discriminant method. The dynamic safety level of the system is determined, and the evolution behavior in the transient process is also performed. The result demonstrates that the hydropower generation system in this study case can operate safely, which is in a good agreement with the corresponding theory and actual engineering. Thus, the framework of dynamic safety assessment aiming at transient processes will not only provide the guidance for safe operation, but also supply the design standard for hydropower stations.

scholarly journals A Review of the Transient Process and Control for a Hydropower Station with a Super Long Headrace Tunnel

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2994 ◽  
Author(s):  
Wencheng Guo ◽  
Daoyi Zhu
Keyword(s):  
Design Optimization ◽  
Transient Process ◽  
Operating Conditions ◽  
Research Progress ◽  
Hydropower Station ◽  
Operation Conditions ◽  
Hydraulic Design ◽  
Headrace Tunnel ◽  
And Control ◽  
Hydropower Stations

The hydropower station with a super long headrace tunnel is a significant development type for hydropower energy. By constructing a super long headrace tunnel, the huge natural water fall head can be utilized to generate more electricity. With the development of hydropower energy, a hydropower station with a super long headrace tunnel becomes more and more competitive. Compared with a hydropower station with a short headrace tunnel, the transient process and control for a hydropower station with a super long headrace tunnel is much more complicated and becomes an intractable challenge. It is well known that the transient process and control is the basis of the design and operation of a hydropower station. To overcome the challenge of the transient process and control, much research has been carried out. This paper provides a systematic review on the latest research progress of the transient process and control for hydropower stations with a super long headrace tunnel. Firstly, two key issues for the transient process and control, i.e., hydraulic design optimization of the surge tank and operation control of unit, are illuminated. Secondly, for both single surge tanks and surge tanks with special types or combinations, the hydraulic design optimization methods are described. The most disadvantageous design and advantageous operation of surge tanks under combined operating conditions are discussed. Thirdly, the stability and regulation quality of the hydro-turbine governing system under isolated and grid-connected operation conditions are presented. Finally, some trends and recommendations for future research directions are made. A research thought for establishing the complete theory and application system of the transient process and control for hydropower stations with a super long headrace tunnel from the perspective of multi-slice and multi-scale is proposed.

scholarly journals Stability Criterion for Mass Oscillation in the Surge Tank of a Hydropower Station Considering Velocity Head and Throttle Loss

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5247
Author(s):  
Wei Huang ◽  
Jiming Ma ◽  
Xinlei Guo ◽  
Huokun Li ◽  
Jiazhen Li ◽  
...  
Keyword(s):  
Stability Criterion ◽  
Influencing Factor ◽  
Hydropower Station ◽  
Velocity Head ◽  
Surge Tank ◽  
Critical Stability ◽  
Basic Equations ◽  
Pumped Storage ◽  
The Stability ◽  
Hydropower Stations

Surge tanks (STs) are important facilities for ensuring the safety of hydropower stations. Reducing the ST size under the premise of ensuring stable mass oscillations within the ST is the main issue. First, according to the basic equations of the mass oscillation for a hydropower station with an ST, a novel expression of the critical stability section of an ST is deduced considering the velocity head and throttle loss. Then, the sensitivity of each influencing factor of the proposed stability criterion is analyzed. Ultimately, through the simulation of small oscillation transients in two case studies, the water level oscillations (WLOs) in an ST based on three stability criteria are compared. The results show that a 20% smaller ST in a hydropower station may result in 10.4% larger oscillations and a 60% smaller ST in a pumped storage power station may result in 14.3% larger oscillations. Compared with the Thoma criterion and the Chinese specification criterion, the stability criterion proposed in this paper can safely reduce the size of the ST since it considers the influence of the velocity head and throttle loss. The proposed stability criterion can provide an important reference for the optimal design of the STs.

scholarly journals Stability Analysis of Jointed Rock Slope by Strength Reduction Technique considering Ubiquitous Joint Model

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Ruili Lu ◽  
Wei Wei ◽  
Kaiwei Shang ◽  
Xiangyang Jing
Keyword(s):  
Rock Slope ◽  
Reduction Method ◽  
Domain Size ◽  
Jointed Rock ◽  
Strength Reduction ◽  
Hydropower Station ◽  
Strength Reduction Method ◽  
Vertical Side ◽  
The Stability ◽  
Jointed Rock Slope

In order to study the failure mechanism and assess the stability of the inlet slope of the outlet structure of Lianghekou Hydropower station, the strength reduction method considering the ubiquitous joint model is proposed. Firstly, two-dimension numerical models are built to investigate the influence of the dilation angle of ubiquitous joints, mesh discretization, and solution domain size on the slope stability. It is found that the factor of safety is insensitive to the dilation angle of ubiquitous joints and the solution domain size but sensitive to the mesh discretization when the number of elements less than a certain threshold. Then, a complex three-dimension numerical model is built to assess the stability of the inlet slope of the outlet structure of Lianghekou Hydropower station. During the strength reduction procedure, the progressive failure process and the final failure surface of the slope are obtained. Furthermore, the comparison of factors of safety obtained from strength reduction method and analytical solutions indicates that the effect of vertical side boundaries plays an important role in the stability of jointed rock slope, and the cohesive force is the main contribution to the resistant force of vertical side boundaries.

A Study on the Stability of Marine Gas Turbine Generation Module Power System

2012 ◽  
Vol 516-517 ◽  
pp. 1877-1880
Author(s):  
Zhi Tao Wang ◽  
Shu Ying Li ◽  
Xiao Xia Huang ◽  
Tie Lei Li
Keyword(s):  
Energy Storage ◽  
Gas Turbine ◽  
Simulation Models ◽  
Storage Device ◽  
Energy Storage Device ◽  
Generation System ◽  
Heavy Load ◽  
Modular Modeling ◽  
Modular Model ◽  
The Stability

Based on modular modeling idea, the modular model of marine generation system was set by the technology of systematic simulation. One set of simulation models of marine gas turbine generation system was generated. Results show that flywheel energy storage device can enhance the stability of power grid and play a better role in making marine gas turbine generation system stable under heavy load fluctuations.

The Study Summarize of Computational Method on Transition Process in Hydropower Units

2013 ◽  
Vol 457-458 ◽  
pp. 1531-1537
Author(s):  
Bi Ying Wu ◽  
Ning Tang ◽  
Shui Guang Tong
Keyword(s):  
Transient Process ◽  
Transition Process ◽  
Computational Method ◽  
Stable Operation ◽  
Calculation Methods ◽  
Generation System ◽  
Water Power ◽  
Optimization Study ◽  
Start Up ◽  
Power Generation System

In the operation of the hydropower units, it often come across condition changes such as start-up, normal stop, increase or decrease the load and load rejection. This will cause the hydraulic transient process of the water power generation system, which is of great significance to the safe and stable operation of hydropower station. This paper analyzes the method to calculate the transient process of hydropower unit and expounds the principle of all kinds of calculation methods and steps to lay a foundation for further optimization study.

scholarly journals Research on Computer Modeling of Fractional Differential Equation Applied Mathematics

2021 ◽  
Vol 2083 (3) ◽  
pp. 032036
Author(s):  
Linlin Su
Keyword(s):  
Differential Equation ◽  
Time Series ◽  
Hopf Bifurcation ◽  
Equilibrium Solution ◽  
Applied Mathematics ◽  
Bifurcation Diagrams ◽  
Financial Systems ◽  
Fractional Differential ◽  
The Stability ◽  
Evolution Behavior

Abstract This paper qualitatively analyzes the stability of the equilibrium solution of a class of fractional chaotic financial systems and the conditions for the occurrence of Hopf bifurcation, and uses the Adams-Bashford-Melton predictive-correction finite difference method to pass the analysis Bifurcation diagrams, phase diagrams, and time series diagrams are used to simulate the complex evolution behavior of the system.

scholarly journals Technocenological approach to development of power generation of industrial regions

2021 ◽  
Vol 315 ◽  
pp. 03007
Author(s):  
Ivan Paskar ◽  
Fedor Nepsha ◽  
Gennadij Lebedev
Keyword(s):  
Power Generation ◽  
Low Power ◽  
Distributed Generation ◽  
Energy Security ◽  
Power Grid ◽  
Generation System ◽  
Power Sources ◽  
Industrial Regions ◽  
The Stability ◽  
Generation Facility

The prerequisites for the implementation of distributed generation facilities in the power grid complex of the region are highlighted. A technocenological approach has been chosen for the economically and technically sound implementation of power sources. The procedures for the verification and visualization of the technocenosis were carried out, and the stability of the existing generation system was determined. The analysis of the generating complex with the power units expected to be commissioned has been carried out. It is concluded that it is necessary to install a distributed generation facility of low power to improve energy security.

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