Search results for "Transformer"
showing 10 items of 96 documents
A Comparison of Special Bonding Techniques for Transmission and Distribution Cables
2020
In this paper, a review of the existing special bonding techniques for medium voltage (MV) and high-voltage (HV) cables is presented. Special bonding techniques have the purpose of reducing sheath currents, thereby limiting copper losses and the reduction of the ampacity of cables. The authors present a literature review to identify various bonding techniques and how these have evolved over the years thanks to new technologies. Simulations of the most used techniques have been performed in Matlab/Simulink, to compare their strengths and drawbacks.
Thermal simulation of a power transformer
2019
In the article we propose a method of thermally constructive optimization of a 110/20 kV power transformer by numerical simulation (by the finite element method) of the thermal field in the transformer. The thermal simulation was done in the Comsol module called Heat Transfer Module, based on the documentation in Catia V5, and the experimental validation was done by thermography.
Magnetic Field and Short-Circuit Reactance Calculation of the 3-Phase Transformer with Symmetrical Amorphous Core
2006
Magnetically symmetric, 3- phase transformer has been analysed. For the two variants of the windings, the calculation results have been compared with the measured ones. Magnetic flux density components were calculated in and out of the core. The flux distribution and short-circuit reactance have been verified experimentally and a good agreement has been obtained.
Optimal Placements of SVC Devices in Low Voltage Grids with High Penetration of PV Systems
2018
With the increase of load demand and distributed photovoltaic (PV) systems on the electric grid, maintaining the required voltage tolerance at the point delivery (customer homes/businesses) is becoming more challenging for electric power utilities. In a residential neighborhood, the peak load typically occurs in the early evening hours while maximum PV generation occurs during mid day. As a result, the lowest voltage operating points occur in the evening hours; whereas the highest voltage operating point occur during the day, when the PV systems are injecting more power than what is locally consumed. Static VAR Compensators (SVCs) can be used to mitigate voltage violations and smooth out th…
Comparison between complete and simplified methods for determining the microwave noise parameters of HEMTs
1994
Modem automatic noise parameter measuring systems are based on measurements of some values of F(rs ) for different values of IГs (more than four, for redundancy) realized by adjusting an admittance transformer (tuner) inserted between the noise source and the TUT mput . Such values are then manipulated by means of proper data processing techniques using eqn.( 1) [ 11. This measuring procedure is hereafter referred to as standard to point out that the old `Standards on methods of measuring noise in linear twoports´ published by the IRE Subcommittee on noise in 1960 is considered obsolete by all the experimenters.
Datora ģenerēta dzeja
2022
Pēdējos gados ir bijuši vairāki mēģinājumi ar datora palīdzību automātiski ģenerēt arī ko radošu – vizuālās mākslas radīšana, radoša teksta ģenerēšana vai pat mūzikas skaņdarbu komponēšana – šīs ir tikai dažas no jomām, ar kurām darbojas mākslīgais intelekts. Dabiskās valodas ģenerēšana ir visai daudzsološa mākslīgā intelekta un datorlingvistikas apakšnozare, kuras galvenais mērķis ir izstrādāt datorprogrammas, kas spēj radīt cilvēkiem uztveramu tekstu. Starp automātiski ģenerētajiem teksta veidiem var atrast pat dažādas laika prognozes, biogrāfijas, kā arī tekstus, kas ietver sevī radošumu – dažādus stāstus, jokus vai dzeju. Automātiskā dzejas ģenerēšana ir šķietami sarežģīts uzdevums un ļ…
Dabiskās Valodas Dziļo Neironu Tīklu Ģeneratora GPT-2 Sniegums Latviešu un Angļu Valodā
2021
Darbs ir veltīts dabiskās valodas apstrādes tēmas un modeļa GPT-2 izpētei un tā snieguma novērtēšanai angļu valodā, kā arī pielāgota valodas modeļa realizēšanai un apmācībai tekstu ģenerēšanai arī latviešu valodā. GPT-2 ir liels dabiskās valodas apstrādes modelis, kas ir paplašināts no GPT modeļa, daudzkārt palielinot modeļa parametru skaitu un apmācot to uz vairāk treniņa datiem. GPT-2 modeļa apmācībai izmantots valodas korpuss no interneta mājaslapu tekstiem, atšķirībā no GPT modeļa, kura apmācībai izmantots valodas korpuss no grāmatu tekstiem. Šis modelis ir radīts ar mērķi paredzēt nākamo vārdu, ņemot vērā iepriekš esošos vārdus konkrētā tekstā. Apstrādājot iepriekš dotu tekstu, ar GPT-…
Dielectric and mechanical assessment of cellulosic insulation during transformer manufacturing
2021
Due to the impact of cellulose of paper insulation on transformer life, it is imperatire to remove moisture from the oil and the solid insulation. Several techniques have been implemented during manufacturing of power transformers to reduce water content in transformers. These drying processes can involve different costs and time, and they can damage the insulation paper. In this work, a drying process has been implemented in the laboratory trying to simulate the most aggressive conditions that can be suffered by the paper in transformer manufacturing in a real industry. Once the moisture content of papers was lower than 0.5%, the effect of the drying process on paper degradation was evalua…
A review of health assessment techniques for distribution transformers in smart distribution grids
2020
Due to the large number of distribution transformers in the distribution grid, the status of distribution transformers plays an important role in ensuring the safe and reliable operation of the these grids. To evaluate the distribution transformer health, many assessment techniques have been studied and developed. These tools will support the transformer operators in predicting the status of the distribution transformer and responding effectively. This paper will review the literature in the area, analyze the latest techniques as well as highlight the advantages and disadvantages of current methodologies.
Elektromašīnas, 1. daļa: Transformators [lekciju konspekts]
1941
Konspekts ar rokraksta tiesībām. Lasīts Latvijas Valsts Universitātes Mehānikas fakultātē.