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Wyszukujesz frazę "transients" wg kryterium: Wszystkie pola


Wyświetlanie 1-12 z 12
Tytuł:
The modeling of centrifugal pump transients
Autorzy:
Szymczyk, J.
Karaśkiewicz, K.
Powiązania:
https://bibliotekanauki.pl/articles/175255.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
rotodynamic pumps
complete pump characteristics
transients
Opis:
Centrifugal pumps are part of larger hydraulic systems. These hydraulic machines can work not only in the pumping mode but in a number of other modes whose job description is possible using complete characteristics. Some of these modes, such as the turbine mode and the reversed turbine mode, may have practical significance. Knowledge of the transition from one steady state to another state allows to estimate instantaneous values such as, e.g., flow current and torque, which may be even a few times higher than nominal. The principal issues in these transients are amplitudes of parameters of these pumps and the time constants associated with the characteristics of the system.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2015, 130; 83-92
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of transformer modeling on riser pole arresters behavior during switching transients
Autorzy:
Abbaszadeh, A.
Abedi, M.
Doustmohammadi, A.
Powiązania:
https://bibliotekanauki.pl/articles/140474.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
arresters
ATP software
ferroresonance
transformer
power system transients
Opis:
Arresters are widely used in power systems to protect other equipment against overvoltages. However, in some conditions, they can’t operate successfully. One of the disturbances leading to the failure of the riser pole arresters is the ferroresonance overvoltages. In this paper, at first the influence of different transformer simulation models of ATP software on the occurrence of ferroresonance is studied and then the effect of ferroresonance on the riser pole arrester has been scrutinized through the thermal and electrical performance of the arrester in an underground distribution system. The results show that the arrester temperature rises due to energy dissipation in a ferroresonance circumstance, which indeed may result into the explosion of the arrester. Also, applying different models of the transformer in the ATP software and comparing the results, it is shown that the available models do not show the same effect on the arrester.
Źródło:
Archives of Electrical Engineering; 2017, 66, 4; 717-730
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Output characteristics of step-down (Buck) power converter
Autorzy:
Janke, W.
Bączek, M.
Walczak, M.
Powiązania:
https://bibliotekanauki.pl/articles/201669.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
DC-DC converters
output characteristics
load transients
Opis:
The output characteristics of switched-mode dc-dc buck power converter are discussed. The shape of output characteristics is especially important for converters used for supplying modern processors. An output impedance is usually used for description of output characteristics. Many efforts are described in the literature to obtain the satisfastory features of closed-loop output impedance. Another approach, presented in the paper, is based on the concept of the output voltage response corresponding to the load conductance change, and is expressed by hr transmittance. Simulations of output characteristics of the buck converter in frequency and in time-domain have been performed for the ideal case as well as for a more realistic situation, with the parasitic resistances of converter elements included. The measurement results differ substantially from characteristics calculated for an ideal converter and are in good consistency with simulations including parasitics.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2012, 60, 4; 751-755
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation on ferroresonance due to power transformer energization in high voltage 400 kV transmission grid
Autorzy:
Polewaczyk, Mateusz
Robak, Sylwester
Szewczyk, Marcin
Powiązania:
https://bibliotekanauki.pl/articles/141509.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ferroresonance
high voltage
Poincaré map
power system transients
PSCAD
Opis:
This paper presents a study on ferroresonance occurring in a high voltage 400 kV transmission grid due to energization of power transformer under no-load conditions. The system scenarios analyzed in the present paper are considered as critical for development and modernization plans as currently announced by the national grid operator in Poland. The PSCAD simulation model was developed and applied for several study cases of a system with double-circuit arrangement of a transmission line. It is shown that the ferroresonant oscillations can be initiated by two-phase switching operation of a line circuit breaker. The impact of the double-circuit length on the ferroresonance mode and severity is demonstrated with the use of the Poincaré map analysis and Short Time Fourier Transform. It is demonstrated that the length of the transmission line that is mutually coupled in the double-circuit arrangement has a significant impact on the ferroresonance occurrence and on its mode. As the ferroresonance can pose severe threat to the power system components due to the severe overvoltage and overcurrent oscillations, the analysis presented in this paper demonstrates the necessity of the ferroresonance analyses for any re-designed transmission system.
Źródło:
Archives of Electrical Engineering; 2019, 68, 4; 771-786
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analytical calculations of surges caused by direct lightning strike to underground intrusion detection system
Autorzy:
Aniserowicz, K.
Powiązania:
https://bibliotekanauki.pl/articles/200287.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
lightning
transients
overvoltages
analytical modeling
underground cable
błyskawica
transjenty
przepięcia
modelowanie analityczne
kabel podziemny
Opis:
The paper presents an analysis of overvoltages caused by a direct lightning strike in intrusion detection system equipped with underground radiating cable sensors. Waveforms of currents and voltages in the system components are calculated using analytical formulas basing on a transmission-line model in the frequency domain. The time-domain waveforms are computed using the inverse fast Fourier transform (IFFT). Three network configurations of the intrusion detection system are analyzed.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2019, 67, 2; 263-270
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of synchronous generators for the analysis of frequency transients above 1 Hz/s
Autorzy:
Assenkamp, Alf
Powiązania:
https://bibliotekanauki.pl/articles/2135729.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
control system
distributed energy systems
frequency support
generator model
RoCoF
synchronous generators
synchronous machines
Opis:
Large synchronous generators are of high importance for the stability of power systems. They generate the frequency of the system and stabilize it in case of severe grid faults like trips of large in-feeders or loads. In distributed energy systems, in-feed via inverters will replace this generation in large parts. Modern inverters are capable of supporting grid frequency during severe faults by different means on the one hand. On the other hand, higher Rates of Change of Frequency (RoCoF) after incidents need to be accustomed by future systems. To be able to analyse the RoCoF withstand capability of synchronous or induction generators, suitable models need to be developed. Especially the control and excitation system model need enhancements compared to models proposed in standards like IEEE Std 421.5. This paper elaborates on the necessary modelling depth and validates the approach with example results.
Źródło:
Archives of Electrical Engineering; 2022, 71, 3; 687--700
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transients of electrical and mechanical quantities of a brushless DC motor - computations, measurements
Autorzy:
Ciurys, M.
Dudzikowski, I.
Powiązania:
https://bibliotekanauki.pl/articles/141324.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
maszyna elektryczna
silnik bezszczotkowy
magnes trwały
silnik BLDC
obliczenia
pomiary
electrical machines
BLDC motors
permanent magnets
computations
measurements
Opis:
The paper presents a method of computing electrical and mechanical variables of BLDC motors. It takes into account electrical, magnetic and mechanical phenomena in the power supply-converter-BLDC motor-load machine system. The solution to the problem is the so-called circuit-field method. The results determined with the use of time stepping finite element method were used as the parameters of equations of the developed mathematical model. Losses in the motor, losses in transistors and diodes of the converter as well as the actual back EMF waveforms, variable moment of inertia and variable load torque are accounted for. The designed laboratory stand and the test results are presented in the paper. The experimental verification shows the correctness of the developed method, algorithm and program. The developed computational method is universal with respect to different electromechanical systems with cylindrical BLDC motors. It can be applied to electromechanical systems with BLDC motors operating at constant but also variable load torque and moment of inertia.
Źródło:
Archives of Electrical Engineering; 2011, 60, 1; 23-34
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transient recovery voltage analysis for various current breaking mathematical models: shunt reactor and capacitor bank de-energization study
Autorzy:
Oramus, P.
Chmielewski, T.
Kuczek, T.
Piasecki, W.
Szewczyk, M.
Powiązania:
https://bibliotekanauki.pl/articles/140943.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
arc modelling
overvoltages studies
EMTP-ATP program
transients analysis
Opis:
Electric arc is a complex phenomenon occurring during the current interruption process in the power system. Therefore performing digital simulations is often necessary to analyse transient conditions in power system during switching operations. This paper deals with the electric arc modelling and its implementation in simulation software for transient analyses during switching conditions in power system. Cassie, Cassie-Mayr as well as Schwarz-Avdonin equations describing the behaviour of the electric arc during the current interruption process have been implemented in EMTP-ATP simulation software and presented in this paper. The models developed have been used for transient simulations to analyse impact of the particular model and its parameters on Transient Recovery Voltage in different switching scenarios: during shunt reactor switching-off as well as during capacitor bank current switching-off. The selected simulation cases represent typical practical scenarios for inductive and capacitive currents breaking, respectively.
Źródło:
Archives of Electrical Engineering; 2015, 64, 3; 441-458
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of the stator inductances of the expanded Park model and an approach on parameter identification using the evolution strategy
Autorzy:
Schmuelling, Ch.
Kreischer, Ch.
Gołebiowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/141147.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
evolution strategy
FEM
Park equations
Park theory
synchronous machines
transients
Opis:
Commonly, the Park model is used to calculate transients or steady-state operations of synchronous machines. The expanded Park theory derives the Park equations from the phase-domain model of the synchronous machine by the use of transformations. Thereby, several hypothesis are made, which are under investigation in this article in respect to the main inductances of two different types of synchronous machines. It is shown, that the derivation of the Park equations from the phase-domain model does not lead to constant inductances, as it is usually assumed for these equations. Nevertheless the Park model is the most common analytic model of synchronous machines. Therefore, in the second part of this article a method using the evolution strategy is shown to obtain the parameters of the Park model.
Źródło:
Archives of Electrical Engineering; 2016, 65, 3; 585-599
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Control of operability of Peltier modules in cooling systems based on the analysis of transient operating modes
Autorzy:
Kuzichkin, Oleg Rudolfovich
Konstantinov, Igor Sergeevich
Vasilyev, Gleb Sergeevich
Surzhik, Dmitry Igorevich
Powiązania:
https://bibliotekanauki.pl/articles/1845461.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
thermoelectric system
agriculture
complex
transients
peltier effect
identification algorithms
Opis:
The paper is devoted to the control of operability of Peltier modules based on the analysis of transient modes of their operation. Advantages of using low-power thermoelectric modules for the development of thermoelectric plants with adaptive control systems for the needs of the agricultural complex, which significantly reduce their cost characteristics, are shown. The problem of using the stationary mode of their operation, associated with the low efficiency of the modules, as well as the dynamic mode, associated with the presence of transient processes, is indicated. It is noted that overcoming this problem requires solution of the task of automation of reliability providing the well-known approaches to its solution are shown, for which the key advantages and disadvantages are given. An approach is proposed to complex control of the operability and quality of thermoelectric modules during their expluatation in three components of the physical process of thermoelectric conversion (Peltier thermoelectric effect, electrical and thermal transfer phenomena) by analyzing transients in the system based on identification algorithms. To justify it, the necessary equations and mathematical relations are given. Aprobating of the proposed approach was carried out experimentally by determining the time constants for operable and defective commercially available modules and showed its significant advantages over the standard verification procedure.
Źródło:
Archives of Thermodynamics; 2021, 42, 2; 31-42
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A coupled field-circuit model of a 5-phase permanent magnet tubular linear motor
Autorzy:
Tomczuk, B.
Waindok, A.
Powiązania:
https://bibliotekanauki.pl/articles/141318.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
silnik synchroniczny liniowy
magnes trwały
PMLSM
metoda polowo-obwodowa
symulacja
parametry sterowania
permanent magnet linear synchronous motors
field-circuit method
simulation of the transients
control parameters
Opis:
A method for modeling of the dynamics characteristics for a 5-phase permanent magnet tubular linear motor (PMTLM) is presented. Its electromagnetic nonlinear field analysis with finite element method (FEM) has been coupled with the circuit model. The calculation model includes the equations for electrical circuits and mechanical quantities as well. They have been obtained using Lagrange's method. The calculated and measured waves of the mover position have been compared for several values of the excitation current. This comparison yields a good agreement. Presented calculation model is very useful in designing and optimization of the PMTLM and in the calculation of the parameters for the control algorithms intended for such a type of actuators.
Źródło:
Archives of Electrical Engineering; 2011, 60, 1; 5-14
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multi-spark modeling of very fast transient overvoltages for the purposes of developing HV and UHV gas-insulated switchgear and of conducting insulation co-ordination studies
Autorzy:
Szewczyk, M.
Powiązania:
https://bibliotekanauki.pl/articles/200835.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
very fast transient overvoltages
VFTO
gas insulated switchgear
GIS
disconnector switch
DS
modeling
simulations
transients
switching
mitigation
breakdown voltage
BDV
odłącznik
modelowanie
symulacje
transjenty
przełączanie
łagodzenie
rozdzielnice izolowane gazem
Opis:
Very fast transient overvoltages (VFTO) originate from steep voltage breakdowns in SF6 gas that are inherent to operation of any switching device of the gas-insulated switchgear (GIS) type. For power stations with voltage ratings exceeding 500 kV, the ratio between equipment rated- and withstand-voltage levels becomes relatively low, which causes the VFTO peak values to reach the component’s insulation withstand-voltage levels, thus becoming a design factor for high- and ultra-high voltage GIS. While well-established approach to VFTO analyses involves only single VFTO events (the so-called single-spark approach), there is often the need to analyze the entire VFTO generation process, for which the multi-spark approach to VFTO modeling is to be employed. The multi-spark approach allows one to evaluate the VFTO impact on the GIS disconnector design along with the impact of the VFTO on selection and dimensioning of the VFTO damping solutions. As the multi-spark approach to VFTO modeling is now being increasingly used in UHV GIS developments as well as for the insulation co-ordination studies of power stations, the present paper is motivated by the need to report on the VFTO multi-spark modeling approach and to lay a common ground for development works that are supported extensively with VFTO simulations. The paper presents physical assumptions and modeling concepts that are in use in such modeling works. Development of the multi-spark GIS disconnector model for VFTO simulations is presented, followed by an overview of examples of the model application for the GIS development works and for insulation co-ordination studies.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2017, 65, 6; 871-882
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-12 z 12

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