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Tytuł:
Evaluation of the Technical Condition of the Active Part of the High Power Transformer Based on Measurements and Analysis of Vibroacoustic Signals
Autorzy:
Borucki, S.
Cichoń, A.
Majchrzak, H.
Zmarzły, D.
Powiązania:
https://bibliotekanauki.pl/articles/176397.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
vibration
vibroacoustic method
core
power transformer
transformer diagnostics
Opis:
This article presents the results of research connected with the development and industrial use of vibroacoustic methods for the evaluation of the technical condition of the active part of transformers. The article presents the results of the analysis of vibrations generated by the high power transformer in which a defect was found on the basis of tests of oil carried out using the chromatography tests. In order to confirm the damage of the active part of this transformer, vibroacoustic measurements were performed in three states of its operation. The measurement using the classical vibroacoustic method included the registration of vibrations at the idle speed and during the load operation of the transformer. The original diagnostic method, so-called the modified vibroacoustic method, was also used during the measurement. The analysis of signals recorded using the classical vibroacoustic method was carried out in the frequency domain by indicating the amplitude of even harmonic vibrations. However, the analysis of signals measured during the commissioning of the transformer was conducted in the time-frequency domain using the short-time Fourier transform (STFT), continuous wavelet transform (CWT), and discrete wavelet transform (DWT). On the basis of the analysis of the results obtained it was stated that the increased level of vibrations of this transformer is a consequence of the loss of rigidity of the mechanical structure of its core.
Źródło:
Archives of Acoustics; 2017, 42, 2; 313-320
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Technical Possibilities of Reducing the Sound Pressure Level Emitted into the Environment by a Power Transformer
Autorzy:
Borucki, S.
Boczar, T.
Cichoń, A.
Powiązania:
https://bibliotekanauki.pl/articles/177473.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
power transformer
corrected sound pressure level
noise
modernization
Opis:
The subject presented in this paper refers to measurements and assessment of the corrected sound pressure level values (noise) occurring around a medium-power transformer. The paper presents the values of noise accompanying the operation of the power object before and after its modernization, which consisted in repeated core pressing and replacement of the cooling system. The main aim of the research work was the assessment of the influence of the repair work on the noise level emitted into the environment.
Źródło:
Archives of Acoustics; 2011, 36, 1; 49-56
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diagnosis of the Non-Concurrent Operation of the On-Load Tap Changer Contacts by the Acoustic Emission Method
Autorzy:
Cichoń, A.
Borucki, S.
Boczar, T.
Powiązania:
https://bibliotekanauki.pl/articles/177044.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
power transformer
on-load tap changers
acoustic emission method
Opis:
On-load tap changers (OLTC) are some of the main transformer elements that make voltage adjustment in a power network possible. Their failures often cause shutdowns of distribution transformers. The paper presents research work aimed at the assessment of the technical condition of OLTCs by the acoustic emission method (EA). This method makes the OLTC diagnosis possible without the need of disconnecting the transformer from the system. The measurements were taken in laboratory conditions. The influence on the operation non-concurrence of the power tap changer contacts on the AE registered signals has been investigated. The signals registered were subjected to analyses in the time and time-frequency domains. The result analysis in the time domain was carried out using the Hilbert transform and calculating characteristic times for the particular runs. A short-time Fourier transform was used for the assessment of results in the time-frequency do- main.
Źródło:
Archives of Acoustics; 2011, 36, 4; 823-830
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Using Clustering Methods for the Identification of Acoustic Emission Signals Generated by the Selected Form of Partial Discharge in Oil-Paper Insulation
Autorzy:
Borucki, S.
Łuczak, J.
Zmarzły, D.
Powiązania:
https://bibliotekanauki.pl/articles/177657.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
acoustic emission method
acoustic signals
partial discharges
insulation
power transformer
Opis:
The article presents the results concerning the use of clustering methods to identify signals of acoustic emission (AE) generated by partial discharge (PD) in oil-paper insulation. The conducted testing featured qualitative analysis of the following clustering methods: single linkage, complete linkage, average linkage, centroid linkage and Ward linkage. The purpose of the analysis was to search the tested series of AE signal measurements, deriving from three various PD forms, for elements of grouping (clusters), which are most similar to one another and maximally different than in other groups in terms of a specific feature or adopted criteria. Then, the conducted clustering was used as a basis for attempting to assess the effectiveness of identification of particular PD forms that modelled exemplary defects of the power transformer’s oil-paper insulation system. The relevant analyses and simulations were conducted using the Matlab estimation environment and the clustering procedures available in it. The conducted tests featured analyses of the results of the series of measurements of acoustic emissions generated by the basic PD forms, which were obtained in laboratory conditions using spark gap systems that modelled the defects of the power transformer’s oil-paper insulation.
Źródło:
Archives of Acoustics; 2018, 43, 2; 207-215
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fault diagnosis of power transformer based on improved particle swarm optimization OS-ELM
Autorzy:
Li, Yuancheng
Ma, Longqiang
Powiązania:
https://bibliotekanauki.pl/articles/140428.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
power transformer
fault diagnosis
improved particle swarm optimization
OS-ELM
parameter optimization
Opis:
A transformer is an important part of power transmission and transformation equipment. Once a fault occurs, it may cause a large-scale power outage. The safety of the transformer is related to the safe and stable operation of the power system. Aiming at the problem that the diagnosis result of transformer fault diagnosis method is not ideal and the model is unstable, a transformer fault diagnosis model based on improved particle swarm optimization online sequence extreme learning machine (IPSO-OS-ELM) algorithm is proposed. The improved particle swarmoptimization algorithm is applied to the transformer fault diagnosis model based on the OS-ELM, and the problems of randomly selecting parameters in the hidden layer of the OS-ELM and its network output not stable enough, are solved by optimization. Finally, the effectiveness of the improved fault diagnosis model in improving the accuracy is verified by simulation experiments.
Źródło:
Archives of Electrical Engineering; 2019, 68, 1; 161-172
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multi-harmonic approach to determine load dependent local flux variations in power transformer cores
Autorzy:
Riemer, B.
Hameyer, K.
Powiązania:
https://bibliotekanauki.pl/articles/141250.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
flux distribution
local flux variations
multi-harmonic FEM
nonlinear FEM
power transformer
Opis:
This paper presents a methodology for the calculation of the flux distribution in power transformer cores considering nonlinear material, with reduced computational effort. The calculation is based on a weak coupled multi-harmonic approach. The methodology can be applied to 2D and 3D Finite Element models. The decrease of the computational effort for the proposed approach is >90% compared to a time-stepping method at comparable accuracy. Furthermore, the approach offers a possibility for parallelisation to reduce the overall simulation time. The speed up of the parallelised simulations is nearly linear. The methodology is applied to a single-phase and a three-phase power transformer. Exemplary, the flux distribution for a capacitive load case is determined and the differences in the flux distribution obtained by a 2D and 3D FE model are pointed out. Deviations are significant, due to the fact, that the 2D FE model underestimates the stray fluxes. It is shown, that a 3D FE model of the transformer is required, if the nonlinearity of the core material has to be taken into account.
Źródło:
Archives of Electrical Engineering; 2015, 64, 1; 129-138
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Power electronic transformer based on cascaded H-bridge converter
Autorzy:
Morawiec, M.
Lewicki, A.
Powiązania:
https://bibliotekanauki.pl/articles/201872.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
power electronic transformer
cascaded H-bridge
rectifier control
control system
transformator mocy
mostek H
system sterowania
Opis:
In this paper the control strategy of power electronic transformer (PET) is proposed. The analyzed structure of PET uses two seven-level cascaded H-bridge (CHB) rectifiers. The electrical power of PET is transferred between DC-links of CHB converters using dual-active-bridges (DABs) and low voltage high frequency transformers. The roposed solution allows for controlling the active and reactive power with a low level of harmonic distortions. The DC-link voltages and the load of the utilized H-bridges are controlled using appropriate modulation strategy. The theoretical issues are confirmed by simulation and experimental results.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2017, 65, 5; 675-683
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Three-phase hybrid transformer using matrix-chopper as an interface between two AC voltage sources
Autorzy:
Kaniewski, J.
Fedyczak, Z.
Szcześniak, P.
Powiązania:
https://bibliotekanauki.pl/articles/950668.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
hybrid transformer
power system
matrix chopper
Opis:
This paper deals with a three-phase power system with hybrid transformer (HT) installed between two AC sources. The main aim of this paper is analyze the basic properties of HT with active load and ability to bidirectional energy flow. The HT contains two main units – a conventional transformer with electromagnetic coupling and PWM AC line chopper connected with secondary windings with electric coupling. The HT is located between the distribution system and a Local Balancing Area (LBA) with low power local energy sources. After describing the HT circuit and three-phase, twosources power system, the mathematical and circuit models of the AC source with HT are presented. These models are verified by means of the simulation and experimental test results obtained for a three-phase HT of about 3 kVA rated power.
Źródło:
Archives of Electrical Engineering; 2014, 63, 2; 197-210
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
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:
Improved modeling of new three-phase high voltage transformer with magnetic shunts
Autorzy:
Chraygane, M.
El Ghazal, N.
Fadel, M.
Bahani, B.
Belhaiba, A.
Ferfra, M.
Bassoui, M.
Powiązania:
https://bibliotekanauki.pl/articles/950652.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
transformer
three-phase
modeling
EMTP
microwaves
power supply
Opis:
This original paper deals with a new approach for the study of behavior in nonlinear regime of a new three-phase high voltage power supply for magnetrons, used for the microwave generators in industrial applications. The design of this system is composed of a new three-phase leakage flux transformer supplying by phase a cell, composed of a capacitor and a diode, which multiplies the voltage and stabilizes the current. Each cell. in turn, supplies a single magnetron. An equivalent model of this transformer is developed taking into account the saturation phenomenon and the stabilization process of each magnetron. Each inductance of the model is characterized by a non linear relation between flux and current. This model was tested by EMTP software near the nominal state. The theoretical results were compared to experimental measurements with a good agreement. Relative to the current device, the new systemprovides gains of size, volume, cost of implementation and maintenance which make it more economical.
Źródło:
Archives of Electrical Engineering; 2015, 64, 1; 157-172
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of electric vehicle charging rates on transformer derating in harmonic-rich battery charger applications
Autorzy:
Jouybari-Moghaddam, M.
Alimardani, A.
Hosseinian, S.H.
Powiązania:
https://bibliotekanauki.pl/articles/140829.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electric vehicle charging
charging rate
power quality
stochastic modeling
transformer derating
Opis:
A study on plug-in electric vehicle (PEV) charging load and its impacts on distribution transformers loss-of-life, is presented in this paper. The assessment is based on residential PEV battery charging. As the exact forecasting of the charging load is not possible, the method for predicting the electric vehicle (EV) charging load is stochastically formulated. With the help of the stochastic model, the effect of fixed, time of use, and real-time charging rates on the charging load and the resultant impact on transformer derating is investigated. A 38-bus test system is adopted as the test system including industrial harmonic sources. Test results demonstrate that uncontrolled EV charging might causes a noticeable change in the K-factor of the transformer, emerging the need for derating, while applying real-time rates for battery charging loads conquers this problem even in case of harmonic-rich chargers.
Źródło:
Archives of Electrical Engineering; 2012, 61, 4; 483-497
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of power losses in a high-frequency planar transformer using a thermal camera
Autorzy:
Barlik, R.
Nowak, M.
Grzejszczak, P.
Zdanowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/140759.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
power losses estimation
thermal camera
thermal calibration
planar transformer
Dowell’s and Steinmetz’s equations
Opis:
This paper presents the implementation of a thermal camera for the quantitative estimation of power losses in a high frequency planar transformer (100 kHz/ 5600 VA). The methodology is based on the observation of the transient temperature rise and determination of the power losses by means of curves representing the derivative of temperature as a function of power losses dissipated in the transformer. First, the thermal calibration characteristics had to be obtained from a simple experiment, where power losses are generated by DC current in the ferrite core and windings. Next, experimental investigations focused on the determination of the transformer power losses for a short circuit and no load, with a resistive load and with the rectifier as a load were carried out. Finally, to verify the obtained results, analytical calculations based on Dowell’s and modified Steinmetz’s equations were additionally made, which showed a good convergence. The proposed method is easy to implement and can be used as an alternative to the calorimetric method which is time-consuming and requires a complicated measurement setup.
Źródło:
Archives of Electrical Engineering; 2016, 65, 3; 613-627
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The impact of smart transformer on different radialdistribution systems
Autorzy:
Mahmoud, Ibrahem Mohamed A.
Abdelsalam, Tarek Saad
Swief, Rania
Powiązania:
https://bibliotekanauki.pl/articles/1841278.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
smart transformer
smart grid
direct approach
power flow
power loss reduction
inteligentny transformator
inteligentna sieć
bezpośrednie podejście
przepływ mocy
redukcja strat mocy
Opis:
The work is intended to extend the application of a smart transformer on a radialdistribution system. In this paper, an updated algorithm on the backward/forward powerflow is introduced. The so-called direct approach of power flow is employed and analyzed.In addition, the paper focused on integrating a smart transformer to the network and solvingthe updating network also using the direct approach load flow. The solution of the smarttransformer using the direct approach power flow method is quite straightforward. Thismodel is applied to radial distribution systems which are the IEEE 33- and IEEE 69-bussystems as a case study. Also, the paper optimizes the best allocation of the smart transformerto reduce the power losses of the grid.
Źródło:
Archives of Electrical Engineering; 2021, 70, 2; 271-283
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of a High-voltage Switching Power Supply Parameters
Autorzy:
Martemianov, Boris
Ryzhkov, Alexander
Vdovin, Grigoriy
Powiązania:
https://bibliotekanauki.pl/articles/2055213.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
high voltage
low power
power supply
microchannel plate
MCP
MCP detector
low signal
Cockcroft-Walton
voltage multiplier
pulse generator
pulse transformer
voltage stabilizer
Opis:
A principle diagram of a high-voltage low-power power supply for devices comprising a microchannel plate (MCP) has been developed. A mathematical model was built according to the developed scheme for a detailed study of the operation of the power supply and the selection of the optimal parameters of its components and obtaining the best output voltages. The power supply circuit comprises a control circuit, a pulse transformer, a voltage multiplier circuit, a feedback circuit, and an input stabilizer. The input stabilizer provides the maintenance of the voltage switched in the primary winding of the transformer at a given level regardless of the voltage drop of the power supply primary source. Moreover the stabilizer provides constant voltage maintenance when the load resistance changes. (with Rload changing from 100 to 200 MΩ, Uout did not exceed 3 V).
Źródło:
International Journal of Electronics and Telecommunications; 2021, 67, 4; 711--716
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling of the AC/HF/DC converter with power factor correction
Autorzy:
Bogdan, A.
Powiązania:
https://bibliotekanauki.pl/articles/141404.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
korekcja współczynnika mocy
obwód rezonansowy
transformator wysokiej częstotliwości
przekształtnik podwyższający napięcie
power factor correction
resonant circuit
high frequency transformer
boost converter
Opis:
In this paper, the power factor correction system consisted of: bridge converter, parallel resonant circuit, high frequency transformer, diode rectifier and LFCF filter is presented. This system is controlled by a pulse density modulation method and the principle of its operation is based on the boost technique. The modeling approach is illustrated by an example using AC/HF/DC converter. Verification of the derived model is provided, which demonstrated the validity of the proposed approach.
Źródło:
Archives of Electrical Engineering; 2010, 59, 3-4; 141-152
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
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