117 research outputs found
Application of neural network observer for on-line estimation of salient-pole synchronous generators' dynamic parameters using the operating data
Parameter identification is critical for modern control strategies in electrical power systems which is considered both dynamic performance and energy efficiency. This paper presents a novel application of ANN observers in estimating and tracking Salient-Pole Synchronous Generator Dynamic Parameters using time-domain, on-line disturbance measurements. The data for training ANN Observers are obtained through off-line simulations of a salient-pole synchronous generator operating in a one-machine-infinite-bus environment. The Levenberg-Marquardt algorithm has been adopted and assimilated into the back-propagation learning algorithm for training feed-forward neural networks. The inputs of ANNs are organized in conformity with the results of the observability analysis of synchronous generator dynamic parameters in its dynamic behavior. A collection of ANNs with same inputs but different outputs are developed to determine a set of the dynamic parameters. The ANNs are employed to estimate the dynamic parameters by the measurements which are carried out within each kind of fault separately. The trained ANNs are tested with on-line measurements to identify the dynamic parameters. Simulation studies indicate the ANN observer has a great ability to identify the dynamic parameters of salient-pole synchronous generator. The results also show that the tests which have given better results in estimation of each dynamic parameter can be obtained
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Semi-stochastic load model for heavy goods electric vehicles depot charging considering the potential for demand side management
Research and development on the electrification of road vehicles have been dominated by light-duty passenger vehicles and vans. Recent developments in Electric Vehicle (EV) technology, however, are bringing attention to the electrification of heavy-duty vehicles and raising questions about fleet charging profiles and related implications for power networks. In this paper, a semi-stochastic model is developed for the simulation of Heavy Goods Electric Vehicle (HGEV) depots' charging demand profiles. The modelling of daily fleet charging profiles, managed and unmanaged, are addressed in this paper to investigate the characteristics of the typical load profile and the potential of demand side management in response to price signals. Issues of charging constraint and optimal depot charging, from a power network perspective, have been applied to understanding how the fleet demand is met. The findings of this work paves the way to study the impacts of heavy-duty vehicle electrification on the network and the maximum power demanded from the grid based on the charging strategies taken. Adoption of flexibility programs or network reinforcement plans around sites of fleet charging can be informed by this study - helping to mitigate the overall stress that the grid could face due to increasing future demands
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A novel approach to Extended System Frequency Response Model for Complex Power Systems (ESFR)
This paper presents a practical medium-order multi-machine Extended System Frequency Response (ESFR) model that is applicable for the frequency study of large, complex power systems or an island portion due to sudden load disturbances or generator outages. The ESFR model is a simplification of the real system and can be used to capture the essential system dynamics behaviour, commonly associated with high-capacity hydro generation and thermal generating units. Classification of power system generations and developing an equivalent unit for each class is proposed by the first step of this two-step method. The above components are put together in a composite frame, which takes into consideration all significant characteristics and factors related to the frequency response of the system. The IEEE standard model with the best performance for each element has been selected via a comparative analysis in single-machine and multi-machine environments. The second step aims to equalize the effective parameters numerically and comprises two sub-steps. The first sub-step identifies the parameters with considerable impacts on the frequency response of the components via sensitivity analysis. The second sub-step involves extensive comparative studies to find the best formulas for determining the equivalent value of the effective parameters. The graphical interface of an advanced power system software with a user-friendly simulation environment was used for the analysis. The results show that the current approach is capable in terms of accuracy and practicality to capture the diversity of the generating resources in modern power systems
Analysis to efficiency discrete covering worker organ when clearing vegetable raw material
In article is executed analysis to efficiency of the functioning the cleansing equipment for different type vegetable cheese: potatoes, carrot, pommel and the other type potatoes. He is indicative of that that much of the cleansing equipment uses as worker organ abrasive put, which improvement is one of the directions of increasing to his efficiency and improvements of his field-performance data. Classical model of the motion club is considered In process of the analysis in camera of the cleansing machine. For optimization of the process peelings is installed path of the motion and is calculated corner of the flight club with cone-shaped chalice. When shaping the models is considered apart taken tuber of the potatoes. Expecting his uniform sphere and without regard influence upon it other club, have defined the path of his motion on cone-shaped chalice and corner, under which tuber flies to wall. The Corner of the slopping cone chalices 30 degrees took to horizon. Integrating equation on time, got the equation of the energy balance, from which possible select required for peelings time. The Further analysis conducted the methods of the numerical experiment in system Mathcad. Got in this experiment results allow to optimize the drawing a fixing abrasive bands, taking into consideration designed methods of the shaping for such object, as worker organs cleansing machines, technology of the intermittent fixing covering. The Following stage of modeling expected consideration of the process peelings for collection cleaned club, on which expected the separate cleaned objects (for instance, potato tubers) springy element, changing their (in flat production) hard disk united between itself springy spring. Consideration this elaborated models have allowed to install the frequencies of the free fluctuations of this system and, accordingly, moments of the osculation worker organ that in significant measure defines the topology of the abrasive covering
New time-type and space-type non-standard quantum algebras and discrete symmetries
Starting from the classical r-matrix of the non-standard (or Jordanian)
quantum deformation of the sl(2,R) algebra, new triangular quantum deformations
for the real Lie algebras so(2,2), so(3,1) and iso(2,1) are simultaneously
constructed by using a graded contraction scheme; these are realized as
deformations of conformal algebras of (1+1)-dimensional spacetimes. Time-type
and space-type quantum algebras are considered according to the generator that
remains primitive after deformation: either the time or the space translation,
respectively. Furthermore by introducing differential-difference conformal
realizations, these families of quantum algebras are shown to be the symmetry
algebras of either a time or a space discretization of (1+1)-dimensional (wave
and Laplace) equations on uniform lattices; the relationship with the known Lie
symmetry approach to these discrete equations is established by means of twist
maps.Comment: 17 pages, LaTe
Self-Reported Occupational Exposure to HIV and Factors Influencing its Management Practice: A Study of Healthcare Workers in Tumbi and Dodoma Hospitals, Tanzania.
Blood borne infectious agents such as hepatitis B virus (HBV), hepatitis C virus (HCV) and human immune deficiency virus (HIV) constitute a major occupational hazard for healthcare workers (HCWs). To some degree it is inevitable that HCWs sustain injuries from sharp objects such as needles, scalpels and splintered bone during execution of their duties. However, in Tanzania, there is little or no information on factors that influence the practice of managing occupational exposure to HIV by HCWs. This study was conducted to determine the prevalence of self-reported occupational exposure to HIV among HCWs and explore factors that influence the practice of managing occupational exposure to HIV by HCWs in Tanzania. Self-administered questionnaire was designed to gather information of healthcare workers' occupational exposures in the past 12 months and circumstances in which these injuries occurred. Practice of managing occupational exposure was assessed by the following questions: Nearly half of the HCWs had experienced at least one occupational injury in the past 12 months. Though most of the occupational exposures to HIV were experienced by female nurses, non-medical hospital staff received PEP more frequently than nurses and doctors. Doctors and nurses frequently encountered occupational injuries in surgery room and labor room respectively. HCWs with knowledge on the possibility of HIV transmission and those who knew whom to contact in event of occupational exposure to HIV were less likely to have poor practice of managing occupational exposure. Needle stick injuries and splashes are common among HCWs at Tumbi and Dodoma hospitals. Knowledge of the risk of HIV transmission due to occupational exposure and knowing whom to contact in event of exposure predicted practice of managing the exposure. Thus provision of health education on occupational exposure may strengthen healthcare workers' practices to manage occupational exposure
(1+1) Schrodinger Lie bialgebras and their Poisson-Lie groups
All Lie bialgebra structures for the (1+1)-dimensional centrally extended
Schrodinger algebra are explicitly derived and proved to be of the coboundary
type. Therefore, since all of them come from a classical r-matrix, the complete
family of Schrodinger Poisson-Lie groups can be deduced by means of the
Sklyanin bracket. All possible embeddings of the harmonic oscillator, extended
Galilei and gl(2) Lie bialgebras within the Schrodinger classification are
studied. As an application, new quantum (Hopf algebra) deformations of the
Schrodinger algebra, including their corresponding quantum universal
R-matrices, are constructed.Comment: 25 pages, LaTeX. Possible applications in relation with integrable
systems are pointed; new references adde
Atomic contributions to the valence band photoelectron spectra of metal-free, iron and manganese phthalocyanines
The present work reports a photoelectron spectroscopy study of the low-energy region of the valence band of metal-free phthalocyanine (H2Pc) compared with those of iron phthalocyanine (FePc) and manganese phthalocyanine (MnPc). Density Functional Theory calculations have been used to resolve the atomic orbital composition of the valence spectra of all the phthalocyanines (Pcs) analyzed in this study. Moreover we show how the atomic character of the Highest Occupied Molecular Orbital (HOMO) is reflected on the outermost valence band binding energy region. The intensity related to the C 2p contributions, resulting in the HOMO for H2Pc and FePc and in the HOMO-1 for MnPc as described by the theoretical predictions is in very good agreement with the experimental results. The DFT simulations, discerning the atomic contribution to the density of states, indicate how the central metal atom interacts with the C and N atoms of the molecule, giving rise to different partial and total density of states for these three different Pc molecules
Twist maps for non-standard quantum algebras and discrete Schrodinger symmetries
The minimal twist map introduced by B. Abdesselam, A. Chakrabarti, R.
Chakrabarti and J. Segar (Mod. Phys. Lett. A 14 (1999) 765) for the
non-standard (Jordanian) quantum sl(2,R) algebra is used to construct the twist
maps for two different non-standard quantum deformations of the (1+1)
Schrodinger algebra. Such deformations are, respectively, the symmetry algebras
of a space and a time uniform lattice discretization of the (1+1) free
Schrodinger equation. It is shown that the corresponding twist maps connect the
usual Lie symmetry approach to these discrete equations with non-standard
quantum deformations. This relationship leads to a clear interpretation of the
deformation parameter as the step of the uniform (space or time) lattice.Comment: 16 pages, LaTe
A Latency-Aware Real-Time Video Surveillance Demo: Network Slicing for Improving Public Safety
© 2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksWe report the automated deployment of 5G services across a latency-aware, semidisaggregated, and virtualized metro network. We summarize the key findings in a detailed analysis of end-to-end latency, service setup time, and soft-failure detection timeThe research leading to these results has received funding from the EC and BMBF through the METRO-HAUL project (G.A. No. 761727) and OTB-5G+ project (reference No. 16KIS0979K
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