Simulation Studies of the Effect of Shaft's Nonlinear Flexural Stiffness Parameters for Critical States of Rotating Power Transmission Systems

2015 ◽  
Vol 236 ◽  
pp. 62-69
Author(s):  
Tomasz Matyja ◽  
Bogusław Łazarz
Keyword(s):  
Degrees Of Freedom ◽  
Power Transmission ◽  
Flexural Stiffness ◽  
Simulation Studies ◽  
Critical States ◽  
Rotating Machine ◽  
Power Transmission Systems ◽  
Main Component ◽  
6 Degrees Of Freedom ◽  
The Impact

The paper presents simulation studies, performed using Simulink, the impact of nonlinear flexural stiffness of shafts for critical speed range and amplitude of vibration. The tests were performed on the selected model of a rotating machine, consisting of a drive, two torsional vibration dampers, shaft with mounted on it two rigid rotors (discs), supported on a three self-aligning roller bearings and mechanical power receiver (brake). The machine startup and braking with crossing the critical states was simulated using specialized Simulink library, which was developed by authors for analysis of transient states in rotating machines and flexural-torsional couplings. In accordance with the concept of modeling adopted by the authors, rotating system is divided into inertial rigid elements (rotors, bearings, clutches, etc..) and compliance elements (parts of the shaft). The main component of the currently developed library is block modeling rigid rotor with 6 degrees of freedom and with the static and dynamic unbalance. By assumption the library is a modular, expandable and allows modeling the systems of any configuration. The goal of the simulation was to verify how nonlinear flexural stiffness of shaft influences the values of critical speeds and the level of flexural and torsional vibrations.

Modeling and Simulation of Impact Point Prediction Algorithm

2013 ◽  
Vol 347-350 ◽  
pp. 438-442 ◽  
Author(s):  
Zai Ke Tian ◽  
Suo Chang Yang ◽  
De Long Feng ◽  
Yun Zhi Yao
Keyword(s):  
Perturbation Theory ◽  
Degrees Of Freedom ◽  
Prediction Algorithm ◽  
Impact Point ◽  
Guidance Law ◽  
Trajectory Simulation ◽  
Correction Scheme ◽  
Trajectory Correction ◽  
6 Degrees Of Freedom ◽  
The Impact

Trajectory correction projectiles significantly improved shooting accuracy of conventional ammunition.This paper designed an impact point prediction algorithm based on perturbation theory, and proposed trajectory correction scheme based on the impact point prediction algorithm. Based on perturbation theory, getting samples by solving ideal trajectory and typical disturbed trajectory, and solving the coefficients of the prediction model by regression.The 6-degrees of freedom trajectory simulation shows that adopting this correction guidance law, the standard error of the longitudinal falling points of projectiles reduced significantly.

scholarly journals Resilience Assessment and Its Enhancement in Tackling Adverse Impact of Ice Disasters for Power Transmission Systems

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2272 ◽  
Author(s):  
Jiazheng Lu ◽  
Jun Guo ◽  
Zhou Jian ◽  
Yihao Yang ◽  
Wenhu Tang
Keyword(s):  
Sequential Monte Carlo ◽  
Power Transmission ◽  
Fragility Curves ◽  
Meteorological Data ◽  
Simulation Method ◽  
Power Grids ◽  
Economic Losses ◽  
Transmission Systems ◽  
Power Transmission Systems ◽  
The Impact

Ice disasters have frequently occurred worldwide in recent years, which seriously affected power transmission system operations. To improve the resilience of power grids and minimize economic losses, this paper proposes a framework for assessing the influence of ice disasters on the resilience of power transmission systems. This method considers the spatial–temporal impact of ice disasters on the resilience of power transmission systems, and the contingence set for risk assessment is established according to contingency probabilities. Based on meteorological data, the outage models of power transmission components are developed in the form of generic fragility curves, and the ice load is given by a simplified freezing rain ice model. A cell partition method is adopted to analyze the way ice disasters affect the operation of power transmission systems. The sequential Monte Carlo simulation method is used to assess resilience for capturing the stochastic impact of ice disasters and deriving the contingency set. Finally, the IEEE RTS-79 system is employed to investigate the impact of ice disasters by two case studies, which demonstrate the viability and effectiveness of the proposed framework. In turn, the results help recognize the resilience of the system under such disasters and the effects of different resilience enhancement measures.

Application of Correlation and Coherence Functions in Diagnostic Systems

2013 ◽  
Vol 196 ◽  
pp. 3-12 ◽  
Author(s):  
Jacek Dziurdź
Keyword(s):  
Autocorrelation Function ◽  
Signal Analysis ◽  
Power Transmission ◽  
Random Noise ◽  
Coherence Function ◽  
Diagnostic Systems ◽  
Power Transmission Systems ◽  
Harmonic Components ◽  
Diagnostic Symptoms ◽  
The Impact

Main problem in operation of diagnostic systems of power transmission systems is analysis of the energy of these harmonic components of the signal, which could be considered as diagnostic symptoms. Measured values can be affected i.a. by energy of random effects or other, less important components of the signal. Coherence and correlation functions are ones of classical methods of signal analysis being applied to analyze deterministic signals affected by random noise. In time domain autocorrelation function allows to determine time cohesion between adjacent fragments of analyzed process, shifted by different time values. In the paper author describes the method of minimization the impact of disturbances on signals being analyzed using basic properties of autocorrelation function. For the analysis of deterministic phenomena (including nonlinear) ordinary coherence function was applied. Showed examples were implemented and solved in MATLAB environment. The method was verified by analysis of model signals and signals (vibration accelerations) recorded on real object.

Development of a general-purpose program based on the concept of subsystem assembly for the analysis of dynamic characteristics of a power transmission system

2000 ◽  
Vol 214 (5) ◽  
pp. 545-560 ◽  
Author(s):  
H-S Jo ◽  
W-J Jang ◽  
W-S Lim ◽  
J-M Lee ◽  
Y-I Park
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Models ◽  
Linear Models ◽  
Power Transmission ◽  
General Purpose ◽  
Transmission Model ◽  
Control Logic ◽  
Design Modification ◽  
Transient Phenomena ◽  
Power Transmission Systems

This paper presents the main algorithms of POTAS-MSM (POwer Transmission Analysis Software for MultiSlipping Mechanism), which are based on the concept of subsystem assembly and the self-determination technique for the system degrees of freedom. This software allows users quickly and easily to model the various and complex configurations of power transmission systems and their components. With these dynamic models, the program can be used to evaluate system performances, transient phenomena such as shift, and other dynamic problems. The program has features for effective handling of non-linear models, rapid examination of the various changes in system behaviour caused by design modification, and provision of stable responses to an arbitrary operating condition or control logic. The ability of the developed program is demonstrated through simulations and experiments of a transmission model.

Increasing On-Shore Wind Generated Electricity in Germany’s Transmission Grid

2014 ◽  
Author(s):  
A. Singh ◽  
D. Willi ◽  
N. Chokani ◽  
R. S. Abhari
Keyword(s):  
Transmission Lines ◽  
Power Transmission ◽  
Mesoscale Model ◽  
Policy Makers ◽  
Transmission Grid ◽  
Energy Projects ◽  
New Energy ◽  
Operational Information ◽  
Power Transmission Systems ◽  
The Impact

An increase in the penetration of renewables generated electricity has technical and economic impacts on power transmission systems because of the renewables’ variable characteristics. However, due to concerns of energy security, operational information of power infrastructure is scarce, making it challenging for policy-makers and independent power producers to assess these systems for the development of new energy projects. This paper presents an analysis of Germany’s power generation and transmission infrastructure using integrated, geographically-indexed production, demand and grid models. The paper assesses the impact of growth of renewables on Germany’s grid in a scenario of slow growth of grid infrastructure to show that the length of transmission lines needing reinforcement increases from 650 km in 2011 to 1090 km in 2020, if Germany’s transmission grid is to keep pace with the increased penetration of renewable energy. Mesoscale model simulations of the weather are used in the year 2020 scenario to assess the economic development of the competing renewables — wind and solar — in relation to the available grid capacity. It is shown that if the grid development lags the development of then targeted 35% renewables portfolio, then 6.5% of generated power by wind and solar energy will face risk of curtailment.

Development of the General-Purposed Program Based on the Concept of Subsystem Assembly for the Analysis of Dynamic Characteristics of Power Transmission System

1999 ◽  
Author(s):  
Weon-Sik Lim ◽  
Han-Sang Jo ◽  
Wook-Jin Jang ◽  
Jang-Moo Lee ◽  
Yeong-Il Park
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Models ◽  
Power Transmission ◽  
Stable Solution ◽  
Self Determination ◽  
Transmission Model ◽  
Control Logic ◽  
Design Modification ◽  
Transient Phenomena ◽  
Power Transmission Systems

Abstract This paper presents the main algorithms of POTAS-MSM (POvver Transmission Analysis Software for Multi-Slipping Mechanism), which are based on the concept of subsystem assembly and the self-determination technique for the system degrees-of-freedom. This software allows users to quickly and easily model the various and complex configurations of power transmission systems and their components. With these dynamic models, the program can be used to evaluate system performances, transient phenomena such as shift, and other dynamic problems. The program has feature to effectively handle nonlinear model, to quickly examine the various changes of system behavior caused by design modification, and to provide stable solution to arbitrary operating condition or control logic. The ability of the developed program is demonstrated through the simulations and the experiments of a transmission model.

scholarly journals The Impact of Superconducting Cables in Power Transmission Systems- a Case Study in Turkey

2020 ◽  
pp. 161-171
Author(s):  
Rıfkı TERZİOĞLU ◽  
Talha Enes GÜMÜŞ ◽  
Mehmet Ali YALÇIN ◽  
Türker Fedai ÇAVUŞ
Keyword(s):  
Power Transmission ◽  
Transmission Systems ◽  
Power Transmission Systems ◽  
The Impact ◽  
Superconducting Cables

Increasing On-Shore Wind Generated Electricity in Germany's Transmission Grid

2014 ◽  
Vol 137 (2) ◽  
Author(s):  
A. Singh ◽  
D. Willi ◽  
N. Chokani ◽  
R. S. Abhari
Keyword(s):  
Transmission Lines ◽  
Power Transmission ◽  
Mesoscale Model ◽  
Policy Makers ◽  
Transmission Grid ◽  
Energy Projects ◽  
New Energy ◽  
Operational Information ◽  
Power Transmission Systems ◽  
The Impact

An increase in the penetration of renewables generated electricity has technical and economic impacts on power transmission systems because of the renewables' variable characteristics. However, due to concerns of energy security, operational information of power infrastructure is scarce, making it challenging for policy-makers and independent power producers to assess these systems for the development of new energy projects. This paper presents an analysis of Germany's power generation and transmission infrastructure using integrated, geographically indexed production, demand. and grid models. The paper assesses the impact of growth of renewables on Germany's grid in a scenario of slow growth of grid infrastructure to show that the length of transmission lines needing reinforcement increases from 650 km in 2011 to 1090 km in 2020, if Germany's transmission grid is to keep pace with the increased penetration of renewable energy. Mesoscale model simulations of the weather are used in the year 2020 scenario to assess the economic development of the competing renewables—wind and solar—in relation to the available grid capacity. It is shown that if the grid development lags the development of then targeted 35% renewables portfolio, then 6.5% of generated power by wind and solar energy will face risk of curtailment.

Computer Simulation Studies of the Adsorption of Water on a Metal Surface

1991 ◽  
Vol 46 (1-2) ◽  
pp. 174-182 ◽  
Author(s):  
E. Spohr ◽  
M. Wolfsberg ◽  
P. Bopp
Keyword(s):  
Degrees Of Freedom ◽  
Adsorbed Molecule ◽  
Simulation Studies ◽  
Impact Zone ◽  
Sticking Coefficient ◽  
Efficient Energy Transfer ◽  
Adsorption Of Water ◽  
Computer Simulation Studies ◽  
Impact Energies ◽  
The Impact

AbstractWe report computer simulations of the adsorption process of water on a platinum (100) surface. At very low impact energies the sticking coefficient approaches unity in agreement with experimental evidence. The sticking coefficient for the bare surface decreases strongly with increasing impact energy already in the energy range <0.5 eV and also with increasing surface temperature. At all but the lowest impact energies the sticking coefficient increases drastically if the impact zone of the approaching molecule is in the vicinity of preadsorbed water molecule(s). The reason for this phenomenon is efficient energy transfer into water-water degrees of freedom and/or into the metal O "bond" of the preadsorbed water molecules. In the present study, where surface diffusion does not play an important role because the impact zone is chosen to be close to the adsorbed molecule or cluster, hydrogen bonds are formed between incoming and preadsorbed molecules during approach and impact. Excess energy is transferred into the lattice within a few picoseconds leading to a two-dimensional hydrogen bonded water cluster.

Mechanically-Tunable Quantum Interference in Ferrocene-Based Single-Molecule Junctions

2020 ◽  
Author(s):  
María Camarasa-Gómez ◽  
Daniel Hernangómez-Pérez ◽  
Michael S. Inkpen ◽  
Giacomo Lovat ◽  
E-Dean Fung ◽  
...  
Keyword(s):  
Single Molecule ◽  
Quantum Interference ◽  
Degrees Of Freedom ◽  
Building Blocks ◽  
Ferrocene Derivative ◽  
Single Molecule Junctions ◽  
Molecule Junction ◽  
Single Molecule Junction ◽  
The Impact ◽  
D Orbitals

Ferrocenes are ubiquitous organometallic building blocks that comprise a Fe atom sandwiched between two cyclopentadienyl (Cp) rings that rotate freely at room temperature. Of widespread interest in fundamental studies and real-world applications, they have also attracted<br>some interest as functional elements of molecular-scale devices. Here we investigate the impact of<br>the configurational degrees of freedom of a ferrocene derivative on its single-molecule junction<br>conductance. Measurements indicate that the conductance of the ferrocene derivative, which is<br>suppressed by two orders of magnitude as compared to a fully conjugated analog, can be modulated<br>by altering the junction configuration. Ab initio transport calculations show that the low conductance is a consequence of destructive quantum interference effects that arise from the hybridization of metal-based d-orbitals and the ligand-based π-system. By rotating the Cp rings, the hybridization, and thus the quantum interference, can be mechanically controlled, resulting in a conductance modulation that is seen experimentally.<br>

Sign in / Sign up

Export Citation Format

Share Document