scholarly journals Research on emergency control mode of sluice gates in water delivery canal

2018 ◽  
Vol 246 ◽  
pp. 01005
Author(s):  
Yan-hua Nie ◽  
Ling-min Liao ◽  
Guo-bing Huang
Keyword(s):  
Control Theory ◽  
Operating Conditions ◽  
Water Diversion ◽  
Control Mode ◽  
Normal Operation ◽  
Water Delivery ◽  
Emergency Control ◽  
Economical Efficiency ◽  
Gate Control ◽  
Hydraulic Response

The regulation of sluice gates（control gates, dividing gates and exit sluices） in water delivery canal is very important and complicated especially in emergency conditions. Most of existing achievements are about canal control theory or based on normal operation condition, lack of researches about emergency joint dispatch under accident conditions and its internal mechanism. In this paper, a mathematical model for emergency dispatch of a long water delivery canal was established to study gate control modes. Some typical operating conditions were selected as study cases and some indicators which could affect safety and economical efficiency of project operation like water level, return water, gate action times were selected as measuring indices. The simulation calculations about different gate control modes of control gates and exit sluices（control speed, open and close time, action frequency, etc）were carried out, through changing gate group control modes to simulate disturbances in emergency regulating process, then track the unsteady flow hydraulic response of channel, analyze the variation of hydraulic parameter, ascertain the relationship between disturbances and channel hydraulic response, summarize the induction mechanism at last. The results can enrich canal gate emergency control theory and improve operation safety and economical efficiency. They can also provide scientific guidances for operation of water diversion projects to enhance emergency disposal ability, and it has strong academic and practical value.

Analysing integration issues of the microgrid system with utility grid network

2021 ◽  
Vol 22 (1) ◽  
pp. 113-127
Author(s):  
Mulualem Tesfaye ◽  
Baseem Khan ◽  
Om Prakash Mahela ◽  
Hassan Haes Alhelou ◽  
Neeraj Gupta ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Distribution System ◽  
Reactive Power ◽  
Renewable Energy Sources ◽  
Operating Conditions ◽  
Control Mode ◽  
Voltage Source ◽  
Modulation Scheme ◽  
Main Challenge ◽  
Utility Grid

Abstract Generation of renewable energy sources and their interfacing to the main system has turn out to be most fascinating challenge. Renewable energy generation requires stable and reliable incorporation of energy to the low or medium voltage networks. This paper presents the microgrid modeling as an alternative and feasible power supply for Institute of Technology, Hawassa University, Ethiopia. This microgrid consists of a 60 kW photo voltaic (PV) and a 20 kW wind turbine (WT) system; that is linked to the electrical distribution system of the campus by a 3-phase pulse width modulation scheme based voltage source inverters (VSI) and supplying power to the university buildings. The main challenge in this work is related to the interconnection of microgrid with utility grid, using 3-phase VSI controller. The PV and WT of the microgrid are controlled in active and reactive power (PQ) control mode during grid connected operation and in voltage/frequency (V/F) control mode, when the microgrid is switched to the stand-alone operation. To demonstrate the feasibility of proposed microgrid model, MATLAB/Simulink software has been employed. The performance of fully functioning microgrid is analyzed and simulated for a number of operating conditions. Simulation results supported the usefulness of developed microgrid in both mode of operation.

Gate control theory and beyond

Pain Forum ◽  
1996 ◽  
Vol 5 (1) ◽  
pp. 40-44 ◽  
Author(s):  
Robert C. Coghill
Keyword(s):  
Control Theory ◽  
Gate Control Theory ◽  
Gate Control

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.

Spinal cord stimulation

2010 ◽  
pp. 161-169
Author(s):  
Brian A. Simpson
Keyword(s):  
Spinal Cord ◽  
Neuropathic Pain ◽  
Control Theory ◽  
Spinal Cord Stimulation ◽  
Gate Control Theory ◽  
Relieve Pain ◽  
Gate Control ◽  
The 1960S

Electricity has been used for centuries to relieve pain but spinal cord stimulation (SCS) came about with the Gate Control Theory in the 1960s SCS was originally thought simply to close the gate by activating A fibres but its effect is more complex. It is likely that it helps to normalize the dysfunction that manifests as neuropathic pain...

scholarly journals Full-Scale Wind Turbine Vibration Signature Analysis

Machines ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 63 ◽  
Author(s):  
Xavier Escaler ◽  
Toufik Mebarki
Keyword(s):  
Wind Farm ◽  
Power Spectra ◽  
Operating Conditions ◽  
Drive Train ◽  
Normal Operation ◽  
Common Source ◽  
Variable Speed ◽  
Data Set ◽  
Vibration Signature ◽  
Power Curves

A sample of healthy wind turbines from the same wind farm with identical sizes and designs was investigated to determine the average vibrational signatures of the drive train components during normal operation. The units were variable-speed machines with three blades. The rotor was supported by two bearings, and the drive train connected to an intermediate three-stage planetary/helical gearbox. The nominal 2 MW output power was regulated using blade pitch adjustment. Vibrations were measured in exactly the same positions using the same type of sensors over a six-month period covering the entire range of operating conditions. The data set was preliminary validated to remove outliers based on the theoretical power curves. The most relevant frequency peaks in the rotor, gearbox, and generator vibrations were detected and identified based on averaged power spectra. The amplitudes of the peaks induced by a common source of excitation were compared in different measurement positions. A wind speed dependency of broadband vibration amplitudes was also observed. Finally, a fault detection case is presented showing the change of vibration signature induced by a damage in the gearbox.

scholarly journals Technical requirements for translucent structures of schools and kindergartens

2019 ◽  
Vol 91 ◽  
pp. 05019
Author(s):  
Aleksandr Konstantinov ◽  
Elena Romanerikova ◽  
Margarita Borisova
Keyword(s):  
Operating Conditions ◽  
Normal Operation ◽  
Future Research ◽  
Natural Lighting ◽  
Technical Requirements ◽  
Standard Construction ◽  
Temperature And Humidity ◽  
Typical Composition ◽  
Room Lighting ◽  
Construction Practice

The article presents some features of the translucent structures design of schools and kindergartens. The analysis of technical requirements for translucent structures of schools and kindergartens was represented. Based on a review of the typical composition of the premises of schools and kindergartens, it was found that different technical requirements should be established for translucent structures installed in rooms of various functional purposes and operating conditions. It was determined that the existing construction practice doesn’t take into account the differentiation of requirements for translucent structures of various premises of schools and kindergartens, and their design, as a rule, is taken to be the same for the entire construction objects. In future, it leads to disruption of the normal operation of the facility (especially in terms of ensuring normal temperature and humidity conditions and natural lighting of the premises). The features of the replacement of translucent structures in reconstructed schools and kindergartens were considered. It has been revealed that the use of modern types of translucent structures of standard construction (first of all, PVC window units) in the reconstruction leads to a significant decrease in the indicators of natural room lighting. Ways to solve this problem were given. Moreover, perspective directions for future research of the issue under consideration were considered.

Numerical simulation of ship propulsion transients and full-scale validation

2003 ◽  
Vol 217 (1) ◽  
pp. 41-52 ◽  
Author(s):  
U Campora ◽  
M Figari
Keyword(s):  
Full Scale ◽  
Operating Conditions ◽  
Dynamics Simulation ◽  
Normal Operation ◽  
System Response ◽  
Prime Mover ◽  
Software Environment ◽  
Simulation Code ◽  
Ship Propulsion ◽  
Wide Range

The paper describes a mathematical model for the dynamics simulation of ship propulsion systems. The model, developed in a MATLAB-SIMULINK software environment, is structured in modular form; the various elements of the system are described as individuals blocks (hull, prime mover, gear, waterjet, etc.) and linked together to take their interactions into account. In this way it is possible to characterize the dynamic behaviour of both the single component and the whole propulsion plant. The model may be used to analyse the system response at off-design and transient conditions. In particular, the developed computer simulation code may be considered as a useful tool to facilitate the correct matching of the prime mover (diesel or gas turbine) to the propulsor (waterjet or propeller) in a wide range of operating conditions. The paper shows the application of the methodology to a cruise ferry used to validate the model results through a full-scale test campaign conducted by the authors during normal operation of the ship.

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