Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

Wyszukujesz frazę "transformers" wg kryterium: Temat


Tytuł:
Identification of Acoustic Emission Signals Originating from the Core Magnetization of Power Oil Transformer
Autorzy:
Olszewska, A.
Witos, F.
Powiązania:
https://bibliotekanauki.pl/articles/177181.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
power oil transformers
magnetization of transformers cores
magnetoacoustic emission
Opis:
In this paper, the properties of AE signals originating from phenomena occurring during magnetization of ferromagnetic materials which are used to construct power transformer cores are presented. The AE signals in a selected power oil transformer were recorded and analyzed. The analysis included, i.e., time, frequency, and time-frequency analyses, calculations of amplitude distributions of the signals and defined AE descriptors, determination of the descriptor map on the side walls of transformers, as well as a detailed analysis of selected part of the signals. The maps of descriptors were analyzed in the frequency bands of 20–70 kHz, 70–100 kHz, and 100–200 kHz. The analysis of the properties of the signals was performed in time and frequency domains. Based on the analysis, there were identified the AE signals originating from the phenomena occurring during the core magnetization of a power oil transformer. To identify those phenomena, the maps of the ADC descriptor calculated in the band of 20–70 kHz when selecting the measurement points in which there were no AE sources from partial discharges were used. An analysis of magnetoacoustic emission signals in the bands of 70–100 kHz and 100–200 kHz was also performed. The analysis of the signal properties in such an extended frequency range allowed determining the properties of the magnetoacoustic signals coming from core sheets of power oil transformers.
Źródło:
Archives of Acoustics; 2016, 41, 4; 799-812
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
PIFA antenna for partial discharge detection in power transformers
Autorzy:
Szymczak, Cyprian
Powiązania:
https://bibliotekanauki.pl/articles/1849124.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
diagnostics of power transformers
reliability of power transformers
partial discharge detection
UHF method
PIFA antenna
Opis:
The article presents the process of designing and manufacturing a prototype antenna based on the PIFA (Planar Inverted F Antenna) technology for the detection of UHF signals from partial discharges occurring in the power transformer insulation system. The main objective of the simulation studies was to obtain a frequency band covering the range of radio frequencies emitted by partial discharges in oil-paper insulation (surface discharges) and to adjust the dimensions of the antenna for its installation in the inspection window of the power transformer. The proposed structure consists of a radiating element in the shape of a rectangular meandering line and an additional parasitic element in the form of a specially selected resistor connecting the reflector with the radiator. The design of the prototype antenna was tested during laboratory tests in a high-voltage laboratory using a model of a transformer tank in which partial discharges were generated. The results of the measurements showed that the developed antenna has a higher sensitivity of partial discharge detection than other popular antennas used in transformer diagnostics, i.e. the disk antenna and the Hilbert fractal antenna. Due to high sensitivity, compact and simple structure and low production costs, the proposed PIFA antenna may be an interesting alternative to the currently used commercial antennas (mainly disk antennas) in on-line monitoring systems for partial discharges of power transformers.
Źródło:
Metrology and Measurement Systems; 2021, 28, 2; 343-355
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Environmental Aspects of Grid Connected Power Electronic Converters Control
Autorzy:
Chmielewski, T.
Powiązania:
https://bibliotekanauki.pl/articles/123499.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
converters
energy
control system
power transformers
Opis:
This paper presents an unconventional view on power electronic converters control as an important factor in environmental protection. Two distinct features that are provided by the control system, namely harmonics elimination and Fault Ride-Through are addressed herein. The paper provides the discussion on how well designed and robust power converter control can influence the environment in a positive way. One of the shortcomings of power converters is emission of current harmonics which results in supply voltage distortion. The appropriate control minimizes the harmonics content which leads to energy losses reduction, especially in power transformers cores. Fault ride-through is an ability of power converter to remain connected and operating in a grid where the fault occurred. It is of paramount importance for integration of large power renewable energy sources. Shutting down e.g. large wind farm would result in engaging the conventional power plants to fill in the energy production gap.
Źródło:
Journal of Ecological Engineering; 2017, 18, 2; 182-191
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal properties of nanoliquids in the aspects of their used in the insulation system of high voltage power transformer
Autorzy:
Dombek, G.
Nadolny, Z.
Przybyłek, P
Powiązania:
https://bibliotekanauki.pl/articles/97610.pdf
Data publikacji:
2014
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
nanoliquids
high voltage power transformers
thermal properties
Opis:
The article presents information concerning the electrical and thermal properties of nanoliquids in the context of their use in the insulating system of high voltage power transformers. It consists of six chapters. The first chapter is an introduction. The second chapter describes properties of the modern insulating nanoliquids created on the basis of mineral oil and nanoparticles. The third chapter is devoted to the measurement systems to the measure of the viscosity, thermal conductivity and density. The fourth chapter presents the methods of preparation of nanoliquids. In the fifth chapter the viscosity, thermal conductivity and density of mineral oil and nanoliquids were compared. Article ends with a summary.
Źródło:
Computer Applications in Electrical Engineering; 2014, 12; 217-226
1508-4248
Pojawia się w:
Computer Applications in Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measuring accuracy of electric energy in HV power networks
Autorzy:
Jałmużny, W.
Powiązania:
https://bibliotekanauki.pl/articles/262655.pdf
Data publikacji:
2005
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie
Tematy:
electric energy measuring
instrument transformers
measuring accuracy
Opis:
The article presents the effect of secondary circuits of inductive current and voltage transformers on measuring accuracy in HV power networks. The basic parameters of instrument transformers were defined, such as errors or rated output. The impedance effect of the leads connecting secondary terminals with measuring instruments and the impact of burden power on the energy measuring error were analyzed. The calculation samples illustrate the procedure when assessing energy (power) measuring error. The algorithm may be applied, with positive results, by the operating personnel of measuring circuits with instrument transformers.
Źródło:
Electrical Power Quality and Utilisation. Journal; 2005, 11, 1; 3-15
1896-4672
Pojawia się w:
Electrical Power Quality and Utilisation. Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The role of the type of insulating liquid in the transformer temperature distribution
Autorzy:
Dombek, G.
Nadolny, Z.
Przybyłek, P.
Powiązania:
https://bibliotekanauki.pl/articles/97345.pdf
Data publikacji:
2016
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
mineral oil
synthetic ester
natural ester
power transformers
Opis:
The mineral oil is most frequently used liquid in insulation transformer system. However, increased interest in alternative insulating liquid for it, which includes synthetic ester and natural ester is observable for several years. However, for several years, the increased interest in insulating liquids as alternatives to mineral oil is observable, which include synthetic ester and natural ester. This is due to increasingly restrictive environmental legislation and fire safety. Mineral oil, in comparison with esters has a very good electric insulation properties and a lower viscosity. In turn the esters in comparison with oil, have a much greater biodegradability and have a much higher flash point, which suggests their favor. The influence of the type of insulating liquid on the efficiency of the cooling system of the transformer was presented in the paper. This efficiency was determined by designating the heat transfer coefficient α by liquids. This factor depends on the thermal properties of liquids, which includes the thermal conductivity λ, kinematic viscosity υ, specific heat cp, density ρ, and thermal expansion β. For the study mineral oil, synthetic ester and natural ester were used. The measurements of thermal properties were carried out in the temperature range from 25°C to 80°C.
Źródło:
Computer Applications in Electrical Engineering; 2016, 14; 148-157
1508-4248
Pojawia się w:
Computer Applications in Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimum EMC design of flyback and load resonant converters using toroids with air gaps
Autorzy:
Stadler, A.
Albach, M.
Durbaum, T.
Powiązania:
https://bibliotekanauki.pl/articles/262737.pdf
Data publikacji:
2005
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie
Tematy:
transformers
toroidal core
magnetic stray field
power converter
Opis:
In this paper the external magnetic stray field is investigated in transformers realized on gapped toroids with a rectangular cross section. An analytical method is used in which the field distribution is calculated by means of orthogonal expansion. As a conclusion it is shown that optimum EMC design for the case of a flyback converter is given by the results for a simple inductor. In case of a load resonant converter minimum parasitic induction is obtained, if the winding conducting maximum current is located exactly above the air gap. The second winding has to be located as close as possible to the first one with respect to the desired value of the total leakage inductance.
Źródło:
Electrical Power Quality and Utilisation. Journal; 2005, 11, 2; 15-22
1896-4672
Pojawia się w:
Electrical Power Quality and Utilisation. Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
TLM-method for computer modeling of transformers’ windings frequency response
Autorzy:
Banaszak, S.
Gawrylczyk, K. M.
Powiązania:
https://bibliotekanauki.pl/articles/376947.pdf
Data publikacji:
2012
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
power transformers
FRA
TLM
frequency response analysis (FRA)
Opis:
The diagnostics of power transformers is a very fast developing branch, due to increasing average age of assets and changes in asset management strategies, nowadays companies introduce asset management based on technical condition. One of important methods used for diagnostics of a transformer’s active part is Frequency Response Analysis (FRA). It allows determination of mechanical condition of windings, their displacements, deformations and electric faults, as well as some problems with internal leads and connections, core and bushings. For the aim of windings impedance modeling the transmission-line models are applied. The idea of TLM was presented in [1], While the length of transformer wires is comparable to wave length at high frequency, such approach is reasonable. The paper presents examples of models created for simple windings.
Źródło:
Poznan University of Technology Academic Journals. Electrical Engineering; 2012, 69; 41-47
1897-0737
Pojawia się w:
Poznan University of Technology Academic Journals. Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design and test of a new high-current electronic current transformer with a Rogowski coil
Autorzy:
Zhang, M.
Li, K.
He, S.
Wang, J.
Powiązania:
https://bibliotekanauki.pl/articles/221051.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Rogowski coil
high-current
electronic current transformers
electrical measurements
Opis:
This paper describes the design and test of a new high-current electronic current transformer based on a Rogowski coil. For better performances, electronic current transformers are used to replace conventional electro-magnetic inductive current transformers based on ferromagnetic cores and windings to measure high-current on the high voltage distribution grids. The design of a new high-current electronic current transformer is described in this paper. The principal schemes of the prototype and partial evaluation results are presented. Through relative tests it is known that the prototype has a wide dynamic range and frequency band, and it can allow high accuracy measurements.
Źródło:
Metrology and Measurement Systems; 2014, 21, 1; 121-132
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis on Acoustic Disturbance Signals Expected During Partial Discharge Measurements in Power Transformers
Autorzy:
Kunicki, Michał
Powiązania:
https://bibliotekanauki.pl/articles/1953519.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
acoustic emission
partial discharge
insulation system
measurements
power transformers
Opis:
This paper presents comparative analysis of various acoustic signals expected during partial discharge (PD) measurements in operating power transformer. Main purpose of the paper is to yield relevant and reliable method to distinguish between various acoustic emission (AE) signals emitted by PD and other sources, with particular consideration of real-life results rather than laboratory simulations. Therefore, selected examples of real-life AE signals registered in seven different power transformers, under normal operation conditions, within few years are showed and analyzed. Five scenarios are investigated, which represent five types of AE sources: PD generated by artificial sources, and next four real-life sources (including PD in working transformer, oil flow, oil pumps and core). Several different signal processing methods are applied and compared in order to identify the PD signals. As a result, an energy patterns analysis based on the wavelet decomposition is found as the most reliable tool for identification of PD signals. The presented results may significantly support the process of interpretation of the PD measurement results, and may be used by field engineers as well as other researchers involved in PD analysis using AE method. Finally, observed properties also provide a solid basis for establishing or improving complete classification method based on the artificial intelligence algorithms.
Źródło:
Archives of Acoustics; 2020, 45, 4; 733-746
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
RLC-models for computer modeling of transformers’ windings frequency response
Autorzy:
Banaszak, S.
Gawrylczyk, K. M.
Powiązania:
https://bibliotekanauki.pl/articles/376937.pdf
Data publikacji:
2013
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
power transformers
FRA
frequency response analysis (FRA)
RLC models
Opis:
The diagnostics of power transformers is a very fast developing branch, due to increasing average age of assets and changes in asset management strategies, nowadays companies introduce asset management based on technical condition. One of important methods used for diagnostics of a transformer’s active part is Frequency Response Analysis (FRA). It allows determination of mechanical condition of windings, their displacements, deformations and electric faults, as well as some problems with internal leads and connections, core and bushings. For the aim of windings impedance modeling the RLC models are applied. The idea of lumped parameters models was presented in [6]. The new universal model basing on circuit solution is developed in this paper. Lumped parameters used are calculated with finite element method and Maxwell package. The examples of models created for simple windings were compared to real measurements.
Źródło:
Poznan University of Technology Academic Journals. Electrical Engineering; 2013, 73; 107-113
1897-0737
Pojawia się w:
Poznan University of Technology Academic Journals. Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mathematical modeling the temperature field of power transformer
Autorzy:
Gościński, P.
Dombek, G.
Nadolny, Z.
Bródka, B.
Powiązania:
https://bibliotekanauki.pl/articles/97688.pdf
Data publikacji:
2016
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
high voltage power transformers
similitude theory
ANSYS CFX
mineral oil
Opis:
High voltage transformer is one of the most important elements of the power system. Due to this reason, it is crucial to properly design and build from mechanical side as well as thermal side. Nowadays, designers of power transformers are using from the many programs that allow you to reduce design time. Additionally, thanks to them, designer can quickly and effectively bring new changes in the construction and see what will be their impact on the work of the transformer. This paper shows design assumptions of the mathematical model of power transformer, the similitude theory which was used to maintain an appropriate scale, and interface of Ansys CFX program, in which simulations of temperature field of power transformer was made.
Źródło:
Computer Applications in Electrical Engineering; 2016, 14; 138-147
1508-4248
Pojawia się w:
Computer Applications in Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Practical use of RLC-models of transformers’ windings for determination of local displacements
Autorzy:
Banaszak, S.
Gawrylczyk, K. M.
Powiązania:
https://bibliotekanauki.pl/articles/97720.pdf
Data publikacji:
2013
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
transformer’s diagnostic
frequency response analysis (FRA)
lumped parameter models
Opis:
The diagnostics of power transformers is a very fast developing branch, due to increasing average age of assets and changes in asset management strategies, nowadays companies introduce asset management based on a real technical condition. One of important methods used for diagnostics of a transformer’s active part is Frequency Response Analysis (FRA). It allows determination of mechanical condition of windings, their displacements, deformations and electric faults, as well as some problems with internal leads and connections, core and bushings. For the aim of windings impedance modeling the RLC models are applied. The idea of lumped parameters models was presented in [6]. The new universal model basing on circuit solution is developed in this paper. Lumped parameters used in calculations are obtained with finite element method and Maxwell package. The examples of models created for simple windings were compared to real measurements.
Źródło:
Computer Applications in Electrical Engineering; 2013, 11; 100-109
1508-4248
Pojawia się w:
Computer Applications in Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On parameters determination of multi-port equivalent scheme for multi-winding traction transformers
Autorzy:
Sobczyk, T. J.
El Hayek, J.
Powiązania:
https://bibliotekanauki.pl/articles/950657.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
multi-winding transformer
equivalent scheme
multi-port circuit
traction transformers
Opis:
This paper aims to present a new equivalent scheme of multi-windings traction transformers, based on multiport purely inductive circuit. The mathematical background of this equivalent scheme is described. The determination of the different scheme elements is made through a finite-elements calculation of both main and leakage inductances, for the case of a four-winding transformer. A procedure is defined, which allows to estimate the values of these elements from some measurements on the transformer at no-load and short-circuit operations. A specific strategy of short-circuit tests is described, allowing to determine all parameters in a rather simple way.
Źródło:
Archives of Electrical Engineering; 2015, 64, 1; 17-27
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Frequency Response Testing of Zero-Sequence Current Transformers for Mining Ground Fault Protection Relays
Autorzy:
Kuliński, Krzysztof
Heyduk, Adam
Powiązania:
https://bibliotekanauki.pl/articles/1844476.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
zero-sequence current transformers
ground-fault protection relays
frequency response
Opis:
In Polish coal mining, medium voltage power distribution networks operate with an insulated neutral point. Zero-sequence current transformers are the basic sensors that generate input signals for earth-fault protection relays. In the literature, the problem of frequency response analysis of various types of current transformers has been examined many times, e.g. [1] [2], but not for zero-sequence current transformers so far. As part of the work, two types of zero-sequence current transformers in the range from 0.1 Hz to 100 kHz were tested. Both the change of the current ratio and the angular shift between the transformer secondary current and the total primary current were analyzed.
Źródło:
International Journal of Electronics and Telecommunications; 2020, 66, 4; 701--705
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies