scholarly journals Identification of measuring part elements of numerical relay protection by its response time

2020 ◽  
Vol 24 (5) ◽  
pp. 1030-1040
Author(s):  
Mikhail Andreev ◽  
◽  
Aleksey Suvorov ◽  
Vladimir Rudnik ◽  
◽  
...  
Keyword(s):  
Mathematical Model ◽  
Response Time ◽  
Digital Filters ◽  
Relay Protection ◽  
Input Circuit ◽  
Analog Filters ◽  
Actuation Time ◽  
Identification Method ◽  
The Moment ◽  
Specific Implementation

The purpose of the study is to develop an identification method of a specific implementation of the elements of the measuring part (intermediate converters, analog filters) and partially computational-logical part (digital filters) of a microprocessor relay protection by the signal actuation time, which, unlike the existing approaches allows to identify and exclude the delays introduced by the executive protection elements. The method of directed graphs is used to form a mathematical model of the measuring part of the microprocessor relay protection. The solution formed as a result of differential equations is implemented using the method of analog implicit continuous integration. The time delays introduced by the input protection circuits are determined as follows: identical signals are fed to the terminal and the mathematical model of protection; signal actuation time is recorded, where the time starting point is the moment the input signal reaches the setpoint and the end point is the moment of the actuation signal occurrence. Having studied 144 different combinations of measuring part elements (intermediate converters, analog filters) and digital filters with a finite impulse response of microprocessor relay protection, the most “optimal” combination has been chosen, which features the least deviation from the response time of a real device in all studied modes as compared with other combinations. The proposed identification method of input circuit elements of microprocessor (numerical) protection is the main way to bring the model closer to a real device. It also enables to receive a table of “typical” response times of protections with the different structure of the measuring part and depending on the specific type of protection terminal choose in practice a predetermined “optimal” internal composition of protection used when setting up protection using their mathematical models.

scholarly journals Modelling the impact of delaying vaccination against SARS-CoV-2 assuming unlimited vaccine supply

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Marcos Amaku ◽  
Dimas Tadeu Covas ◽  
Francisco Antonio Bezerra Coutinho ◽  
Raymundo Soares Azevedo ◽  
Eduardo Massad
Keyword(s):  
Mathematical Model ◽  
Vaccination Campaign ◽  
Vaccination Rate ◽  
Sao Paulo ◽  
The State ◽  
São Paulo ◽  
Health Authorities ◽  
The World ◽  
The Moment ◽  
The Impact

Abstract Background At the moment we have more than 177 million cases and 3.8 million deaths (as of June 2021) around the world and vaccination represents the only hope to control the pandemic. Imperfections in planning vaccine acquisition and difficulties in implementing distribution among the population, however, have hampered the control of the virus so far. Methods We propose a new mathematical model to estimate the impact of vaccination delay against the 2019 coronavirus disease (COVID-19) on the number of cases and deaths due to the disease in Brazil. We apply the model to Brazil as a whole and to the State of Sao Paulo, the most affected by COVID-19 in Brazil. We simulated the model for the populations of the State of Sao Paulo and Brazil as a whole, varying the scenarios related to vaccine efficacy and compliance from the populations. Results The model projects that, in the absence of vaccination, almost 170 thousand deaths and more than 350 thousand deaths will occur by the end of 2021 for Sao Paulo and Brazil, respectively. If in contrast, Sao Paulo and Brazil had enough vaccine supply and so started a vaccination campaign in January with the maximum vaccination rate, compliance and efficacy, they could have averted more than 112 thousand deaths and 127 thousand deaths, respectively. In addition, for each month of delay the number of deaths increases monotonically in a logarithmic fashion, for both the State of Sao Paulo and Brazil as a whole. Conclusions Our model shows that the current delay in the vaccination schedules that is observed in many countries has serious consequences in terms of mortality by the disease and should serve as an alert to health authorities to speed the process up such that the highest number of people to be immunized is reached in the shortest period of time.

DIFFERENTIAL EQUATIONS FOR TRAIN STARTING WITH ELASTIC CONNECTIONS

2021 ◽  
Vol 2 ◽  
pp. 18-26
Author(s):  
I.P. POPOV
Keyword(s):  
Mathematical Model ◽  
Differential Equations ◽  
Friction Force ◽  
Static Friction ◽  
Longitudinal Vibrations ◽  
Maximum Tension ◽  
Inert Mass ◽  
The Moment ◽  
Elastic Couplings ◽  
Selection Of

The starting mode for the train is the most difficult. An effective method of pulling is the selection of coupling clearances. In this case, the cars are set in motion sequentially and the inert mass, as well as the static friction force immediately at the moment of starting, are minimal. This method has two significant drawbacks - a small fixed value of the gaps in the couplings and the shock nature of the impulse transfer. These disadvantages can be avoided by using elastically deformable couplings. The aim of this work is to construct a mathematical model of "easy" starting of a train with elastic couplings. The softening of the train start-off mode is essentially due to the replacement of the simultaneous start-off of the sections with alternate ones. To exclude longitudinal vibrations of the composition, after reaching the maximum tension of the coupling, the possibility of its harmonic compression should be mechanically blocked.

scholarly journals Research on Dynamic Identification of Servo Motor Load Inertia Based on the Error Gain Factor Model

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6664
Author(s):  
Fang Xie ◽  
Fei Yu ◽  
Chaochen An
Keyword(s):  
Factor Model ◽  
Slow Motion ◽  
Gain Factor ◽  
Moment Of Inertia ◽  
Identification Accuracy ◽  
Identification Algorithm ◽  
Servo Motor ◽  
Dynamic Identification ◽  
Identification Method ◽  
The Moment

Aiming at solving the problems of slow motion and positioning deviation caused by the change of the moment of inertia of the servo motor due to different loads, an identification method for the moment of inertia on the basis of the error gain factor model is introduced into the controller, so that the moment of inertia can be obtained accurately and quickly under dynamic conditions. First, the electromagnetic and motion equation of the permanent magnet synchronous motor is built, and the logical relationship between the moment of inertia, torque, speed and other physical quantities is derived, so that the moment of inertia can be dynamically acquired. Second, in order to increase the identification accuracy, an adaptive function is introduced in the inertia identification model to replace the fixed parameters as an error gain factor (EGF). Third, the accuracy parameter is defined, and the identification algorithm on the basis of the EGF model is compared with the accuracy parameters of the existing identification method, which verifies that the improved algorithm has a better accuracy and speed. Finally, on the experimental platform, the working condition of unsteady speed is simulated. It is further verified that the proposed method has a high anti-interference capability.

scholarly journals The issue of loading the material in a vibro-impact grinder

2019 ◽  
Vol 109 ◽  
pp. 00024 ◽  
Author(s):  
Olena Fedoskina ◽  
Valerii Fedoskin ◽  
Anastasiia Loginova
Keyword(s):  
Mathematical Model ◽  
Phase Angle ◽  
Basic Principles ◽  
Working Chamber ◽  
Force Loading ◽  
New Class ◽  
Power Loading ◽  
The Moment ◽  
Rotational Oscillations

The article discusses the basic principles of force loading of a material in a vibro-impact grinder with a vertical and inclined working chamber. It is shown that in a grinder with a vertical working chamber the control of the material loading is limited by the presence of a relationship between the vertical and rotational oscillations of the jaws. Vibro-impact grinder with an inclined working chamber represents a new class of machines. A mathematical model of the process of interaction of the jaw with a piece of material when moving it in the working chamber is presented. Equations and graphical dependencies are obtained, which determine the phase angle of the moment of clamping the piece in the working chamber. The modes of power loading of the material in the working chamber were analyzed.

Separating Perception Time from Response Time: The Slope Transition Paradigm

Perception ◽  
10.1068/p3304 ◽  
2002 ◽  
Vol 31 (3) ◽  
pp. 323-339 ◽  
Author(s):  
Ethel Matin ◽  
David C Nofer ◽  
Lisa Gische
Keyword(s):  
Response Time ◽  
Psychological Refractory Period ◽  
Visual Presentation ◽  
Perceptual Processing ◽  
Capacity Limits ◽  
Set Size ◽  
Perception Time ◽  
The Subject ◽  
The Moment ◽  
Set Size Effects

This paper describes the slope transition paradigm (STP), a variant of rapid serial visual presentation (RSVP) that separates early (perceptual) processing time from total response time. The paradigm is based on a very simple idea: provide varying amounts of time for perceptual processing and find the moment when the subject begins to waste time waiting for more data. That moment is a measure of how much time was actually needed. The method was used in two experiments. Results are discussed in relation to set-size effects, perceptual capacity limits, attentional dwell times, and some related neurophysiological findings. The method appears to tap aspects of information processing that differ from those tapped in studies of the psychological refractory period, the attentional blink, and repetition blindness.

scholarly journals Investigation of the components of the cornering resistance of a tracked vehicle on a solid support base

2021 ◽  
Vol 1 (2) ◽  
pp. 51-62
Author(s):  
B.V. Padalkin ◽  
Keyword(s):  
Mathematical Model ◽  
Reaction Force ◽  
Vertical Axis ◽  
Support Surface ◽  
Tracked Vehicle ◽  
Tracked Vehicles ◽  
Contact Patch ◽  
Minimum Number ◽  
The Moment ◽  
Propulsion Unit

The purpose of the study is to increase the completeness and reliability of approaches to deter-mining the components of the cornering resistance a tracked vehicle, as well as to create a method for their assessment, which will be suitable for practical calculations. The article analyzes two components of the moment of cornering resistance of the tracked vehi-cle, which can be distinguished if we consider the interaction of the caterpillar with the support base through separate contact spots (active sections of the tracks located under the road wheels). The first component arises from the linear movement of the active sections of the tracks. The second is caused by the rotational movement of the contact patch about the vertical axis. The paper presents a mathematical model of the interaction of the propeller and a dense support base, which makes it possible to study the dependence of the components of the moment of corner-ing resistance on the geometric parameters of the undercarriage of a tracked vehicle. The horizontal reaction force in this case is presented as a function of the slip coefficient. The possibility of realiz-ing various adhesion qualities of the propulsion unit in the longitudinal and transverse directions of sliding is provided. The model assumes a preliminary division of the contact patch into a finite number of elementary areas. Since the number of elementary sites affects the result, the article con-ducted a study to determine the minimum number of sites to ensure acceptable accuracy. An analysis of the expressions available in the literature was carried out to determine the speci-fied component of the cornering resistance. The new empirical relationships that better agree with the mathematical model were proposed. The study of several existing tracked vehicles, differing in the mass and size of the track support surface, made it possible to conclude that it is advisable to take into account the moment of cornering resistance of the contact patch for various types of tracked vehicles.

scholarly journals Theoretical Studies of Bounce in Rod-Type Microswitches

2021 ◽  
Vol 346 ◽  
pp. 03034
Author(s):  
E.S. Lyuminarskaya
Keyword(s):  
Differential Equation ◽  
Response Time ◽  
Elastic Element ◽  
Switching Time ◽  
Design Stage ◽  
Theoretical Studies ◽  
Elastic Rod ◽  
Basic Performance ◽  
The Moment ◽  
Improve Reliability

To improve reliability of microswitches, it is necessary to carry out theoretical studies of the switching process both at the moment of switching and at the moment of bouncing. The article presents a dynamic model of microswitches with elastic rod elements, which allows at the design stage to evaluate such basic performance characteristics as response time and contact bounce time. The proposed technique is based on representation of the solution to the differential equation of vibrations of an elastic element in the form of a linear combination of eigenforms and the application of the Bubnov-Galerkin method. Theoretical studies of bounce in a rod microswitch are carried out. It is shown that breakdown precursors of the spacer spring are an increase in the switching time and the time of the first separation in case of bouncing.

scholarly journals То the synchronous work of pulsed sources of seismic waves

2019 ◽  
pp. 75-79
Author(s):  
S. P. Ekomasov
Keyword(s):  
Control System ◽  
Response Time ◽  
Half Space ◽  
Seismic Waves ◽  
Time Interval ◽  
Shock Interaction ◽  
Seismic Efficiency ◽  
Pulse Type ◽  
The Stability ◽  
The Moment

Researches have been made with the use of a hydropneumatic source of seismic waves. This source on the realized efforts of the shock interaction with a soil half-space considerably exceeds all known designs of radiators (sources) of pulse type. In this regard it shows higher seismic efficiency. The most important characteristic of the work of the pulse sources of seismic waves is a stability of the response time — a time interval from the moment of giving of a signal for producing of the blow until the very blow. Only with the achievement of the necessary stability the work in the mode of grouping of sources and accumulation of signals is possible. Features of the formation of response time of a hydropneumatic source are given. The analysis of the assessment of the parameters of synchronism of the pulse sources is made by a modem control system of their work. An influence of the rigidity of the soil on the assessment of stability of the response time and synchronism is shown. The system of the assessment of the stability used in the existing pulse sources at its application does not reflect the actual stability of response time in the radiators possessing a big force of blow.

scholarly journals INVESTIGATION OF THE INFLUENCE OF PRESSING BELTS TENSION OF THE BACK CIRCUIT OF PRESS - SELECTIVE PR-1.5

2018 ◽  
Vol 13 (2) ◽  
pp. 76-76
Author(s):  
Валерий Белов ◽  
Valeriy Belov ◽  
Леонид Рыбаков ◽  
Leonid Rybakov ◽  
Светлана Овчукова ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Experimental Studies ◽  
Field Research ◽  
Test Protocol ◽  
Optimal Value ◽  
The Stability ◽  
The Moment ◽  
The Mathematical Model ◽  
Elastic Characteristics

A brief analysis of suspension mechanisms and ways to improve the quality of press harvesting for flax harvesting is considered. By researching the mathematical model, the authors prove the possibility of increasing the stability of the elastic characteristics of the suspension mechanisms by changing the angle between the levers or changing the geometry of the structure, for example, the attachment point of a two-arm lever. Particular attention is drawn to the new term “reduced rigidity” of the suspension mechanism. Using this notion and the method of its determination, the authors recommend determining the optimal value of the reduced stiffness of the suspension in the way of mathematical modeling and using this indicator as the main optimization parameter. The results of theoretical and experimental studies were presented by the authors in the form of elastic characteristics of the suspension mechanisms. When conducting a study of the mathematical model, it is suggested to take into account the condition of equality of the maximum values of the moments of forces from the action of the tension forces of the belts or the mass of the working element and the moment of forces acting on the side of the tension springs. During the research of the suspension mechanism, the actual dimensions of the PR-1.5 baler design were adopted. At the same time, we briefly describe the design of the improved tensioning mechanism of a baler for flax harvesting. A rather detailed analysis is given by the authors of the obtained elastic characteristics of the suspension mechanism. Some new features of the elastic characteristics of the suspension mechanism that have not been previously detected are described. To confirm the correctness of the reasoning, the authors implemented their research in a real press-picker and conducted field research that confirmed the possibility of improving the quality of the upgraded version of the machine. To confirm the results of the research, the authors presented a fragment of the field test protocol. The task is solved, uniformity of the roll density is ensured and its density is increased.

scholarly journals Building a modification of the SEIRD model of epidemic spread that takes into account the features of COVID-19

2020 ◽  
pp. 14-27
Author(s):  
Нина Игоревна Еремеева
Keyword(s):  
Mathematical Model ◽  
Relative Number ◽  
Rate Of Change ◽  
Distribution Model ◽  
Epidemic Spread ◽  
Infected People ◽  
The Moment ◽  
The Impact ◽  
The Relationship

Статья посвящена построению математической модели SEIIRDm, учитывающей некоторые особенности распространения COVID-19. Представляемая модель построена на основе классической SEIRD-модели распространения эпидемий. В созданной модели, в отличие от базовой, учитывается то, что латентные носители COVID-19 являются в некоторой степени заразными, и что у существенного количества инфицированных болезнь протекает бессимптомно. В SEIIRDm-модели отражен тот факт, что выявленные больные изолируются (госпитализируются) и вероятность заражения от них резко уменьшается, а также, что карантинные меры имеют массовый характер, причем важна как степень их жесткости, так и момент введения. Кроме того, в статье обращается внимание на то, что зависимость между скоростью изменения относительного числа заболевших и относительным количеством заразных и восприимчивых может быть нелинейной, и этот факт отражен в построенной модели. Статья содержит примеры численного прогнозирования развития эпидемиологического процесса, а также моделирования влияния массовых карантинных мер, рассчитанные на основе созданной математической модели. The article is devoted to the construction of a mathematical model that takes into account some features of COVID-19 propagation. The presented model is based on the classic SEIRD epidemic distribution model. The created model, in contrast to the basic one, takes into account the fact that latent COVIND-19 carriers are somewhat contagious and that in a significant number of infected people, the disease is asymptomatic. The SEIIRDm model reflects the fact that identified patients are isolating (hospitalizing) and the probability of infection from them decreases sharply and also that the measures taken over the quarantine are massive moreover, both the degree of their rigidity and the moment of introduction are important. Besides, the article draws attention to the fact that the relationship between the rate of change in the relative number of cases and susceptible and the relative number of infected may be nonlinear, and this fact is reflected in the built model. The article provides examples of numerical forecasting of the development of the epidemiological process as well as modeling the impact of mass quarantine measures, calculated on the basis of the created mathematical model.

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