• Title, Summary, Keyword: Transformer

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Economic Evaluation of HTS Transformer by Predicting Market Penetration Price (초전도변압기 시장진입가격 예측을 통한 경제성 분석)

  • 김종율;이승렬;윤재영
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.53 no.9
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    • pp.507-512
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    • 2004
  • HTS (High Temperature Superconducting) Transformer has the several useful characteristics in the viewpoints of technical and economical. Especially, an HTS transformer replaces the copper wire coils in a conventional transformer with lower loss HTS wire. In addition, inexpensive, environmentally benign liquid nitrogen replaces the conventional oil as the electrical insulation (dielectric) and provides the necessary cooling for the HTS transformer Therefore, the Life-cycle cost of an HTS transformer is much more attractive than conventional because it is more energy efficient, lighter in weight, smaller in size, and environmentally compliant. HTS transformer can be the best way to replace with conventional transformer in the future. In these days, companies world-wide have conducted researches on HTS transformer. A development project for a 154kV HTS transformer is proceeding at a research center and university in Korea. In this paper, we investigate the expected price of HTS transformer to have a merit in viewpoint of economic aspect. First, life-cycle cost of conventional transformer is calculated and based on this, the expected price of HTS transformer is evaluated. which HTS transformer is competitive against conventional transformer.

Evaluate the expected price of HTS transformer for introducing into korean power system (초전도변압기의 계통적용을 위한 예상 시장진입가격 추정)

  • Kim, Jong-Yul;Lee, Seung-Ryul;Yoon, Jae-Young
    • Proceedings of the KIEE Conference
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    • pp.176-178
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    • 2004
  • HTS (High Temperature Superconducting) Transformer has the several useful characteristics in the viewpoints of technical and economical. Especially, an HTS transformer replaces the copper wire coils in a conventional transformer with lower loss HTS wire In addition, inexpensive, environmentally benign liquid nitrogen replaces the conventional oil as the electrical insulation (dielectric) and provides the necessary cooling for the HTS transformer Therefore, the Life-cycle cost of an HTS transformer is much more attractive than conventional because it is more energy efficient, lighter in weight, smaller in size, and environmentally compliant. HTS transformer can be the best way to replace with conventional transformer in the future. In this paper, we investigate the expected price of HTS transformer to have a merit in viewpoint of economic aspect. First, life-cycle cost of conventional transformer is calculated and based on this, the expected price of HTS transformer is evaluated, which HTS transformer is competitive against conventional transformer.

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Finite Element Analysis of Step-down Piezoelectric Transformer with Various Shape (형태의 변화에 따른 강압용 압전변압기의 유한요소해석)

  • Chong, Hyon-Ho;Park, Tae-Gone;Kwon, Oh-Young
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.697-700
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    • 2003
  • This paper presents design and analysis of step-down piezoelectric transformer for application to AC-adapters. These transformers are consist of rectangular type and disk type multilayered piezoelectric ceramic plate. This piezoelectric transformer operated in third thickness resonance vibration mode. Finite element methode(FEM) was used for analysing transformer. Vibration mode and electric field of piezoelectric transformer were simulated at resonance frequency. As results, rectangular type transformer's output voltage was higher than the disk type. But disk type transformer's current was lagger than rectangular type. These results are assumed that disk type transformer's mixed vibration mode influence transformer's output characteristics. From these results, we expect that disk type piezoelectric transformer is more adoptable than rectangular plate type piezoelectric transformer for AC adapters.

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Design of a 33 MVA HTS Transformer with OLTC (OLTC를 고려한 33 MVA 초전도 변압기 설계)

  • Choi, J.H.;Lee, S.W.;Park, M.J.;Kim, W.S.;Choi, K.D.
    • Proceedings of the KIEE Conference
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    • pp.885-886
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    • 2006
  • We have proposed a 100 MVA, 3 phases, 154 kV class HTS transformer which will substitute for 60 MVA conventional transformer. In this paper, we designed conceptually the structure of the superconducting windings of a single phase 33 MVA transformer. The power transformer of 154 kV class has a tertiary winding besides primary and secondary windings. So the HTS transformer should have the 3rd superconducting winding, it makes the cost of the HTS transformer high and the efficiency low. Further more we considered On Load Tap Changer (OLTC) in HTS power transformer. OLTC equipment is required for fitting to a power transformer by which the voltage ratio between the windings can be varied while the transformer is on load. We analyzed the electrical characteristics of the HTS transformer such as magnetic stress and AC loss.

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High Power Density, High Frequency, and High Voltage Pulse Transformer

  • Kim, S.C.;Jeong, S.H.;Nam, S.H.
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • v.11B no.4
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    • pp.180-184
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    • 2001
  • The high operation frequency mainly reduces transformer volume in the power supply. A high frequency and high voltage pulse transformer is designed, fabricated, and tested. Switching frequency of the transformer is 100 kHz. Input and output voltages of the transformer are 250 V and 4 kV, respectively. Normal operation power of the transformer is 3 kW. Maximum volume of the transformer is 400 $cm^3$. The power density is thus 7.5 W/$cm^3$. The transformer will be installed in a metal box that has nominal operation temperature of 85 degree centigrade. The transformer and other high voltage components in the box will be molded with Silicon RTV(Room Temperature Vulcaniza) that has a very low thermal conductivity. Procedure of design and test results are discussed. Analytical as well as experimental results of varous paramters such as transformer loss, leakage inductance, distributed capacitance are also discussed. In addition, thermal analysis results from ANSYS code for three different operation conditions are discussed.

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The Thermal Analysis of Pole Mount Mold Transformer with One-body Molding by Duct Condition (일체형 주상용 몰드변압기의 덕트에 따른 열해석 특성 연구)

  • Cho, Han-Goo;Lee, Un-Yong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.1135-1138
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    • 2003
  • The transformer is major equipment in power receiving and substation facilities. Necessary conditions required for the transformer are compactness, lightness, high reliability, economic advantages, and easy maintenance. The pole-mount transformer installed in distribution system is acting direct role in supply of electric power and it is electric power device should drive for long term. Most of modem transformer are oil-filled transformer and accident is happening considerable. The mold transformers have been widely used in underground substations in large building and have some advantages in comparison to oil-transformer, that is low fire risk, excellent environmental compatibility, compact size and high reliability. In addition, the application of mold transformer for outdoor is possible due to development of epoxy resin. The mold transformer generally has cooling duct between low voltage coil and high voltage coil. A mold transformer made by one body molding method has been developed for small size and low loss. One body molding transformer needs some cooling method because heat radiation between each winding is difficult. In this paper, The thermal analysis of pole mount mold transformer with one body molding by duct condition is investigated and the test result of temperature rise is compared with simulation data.

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Prediction of A Rise in Temperature Distribution of Mold Transformer for Power Distribution System (배전용 몰드변압기에 대한 상승 온도 분포 예측)

  • Lee, Jeong-Keun;Kim, Ji-Ho;Lee, Hyang-Beom
    • 한국정보통신설비학회:학술대회논문집
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    • pp.391-394
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    • 2009
  • In this paper, achieved rise temperature distribution about degradation phenomenon of 2 MVA distribution mold transformer using finite element method (FEM). Usually, life of transformer is depended on temperature distribution of specification region than thermal special quality of transformer interior. Specially, life of transformer by decline of dielectric strength decreases rapidly in case rise by strangeness transformer interior hot spot temperature value permits. Because calculating high-voltage winding and low-voltage winding of mold transformer and Joule's loss of core for improvement these life, forecasted heat source, and high-voltage winding and low-voltage winding of mold transformer and rise temperature distribution of core for supply of electric power and temperature distribution of highest point on the basis of the result Also, calculated temperature rise limit of mold transformer and permission maximum temperature using analysis by electron miracle heat source alculate and forecasted rise temperature distribution by heat source of thermal analysis with calculated result.

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The Design and Performance Test of Mold Transformer for Outdoor Pole (50 kVA 주상용 몰드변압기의 설계 및 특성평가)

  • Cho, Han-Goo;Lee, Un-Yong;HwangBo, Kuk
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.132-137
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    • 2002
  • The mold transformers have been widely used in underground substations in large building and have some advantages in comparison to oil-transformer, that is low fire risk, excellent environmental compatibility, compact size and high reliability. In addition, the application of mold transformer for outdoor is possible due to development of epoxy resin. The mold transformer generally has cooling duct between low voltage coil and high voltage coil. A mold transformer made by one body molding method has been developed for small size and low loss. The life of transformer is significantly dependent on the thermal behavior in windings. To analyse winding temperature rise, many transformer designer have calculated temperature distribution and hot spot point by finite element method(FEM). Recently, numerical analyses of transformer are studied for optimum design, that is electric field analysis, magnetic field, potential vibration, thermal distribution and thermal stress. In this paper, the temperature distribution of 50 kVA pole mold transformer for power distribution are investigated by FEM program and the temperature rise test of designed mold transformer carried out and test result is analyzed compare to simulation data. In this result, the designed mold transformer is satisfied to limit value of temperature and the other property is good such as voltage ratio, winding resistance, no-load loss, load loss, impedance voltage and percent regulation.

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Intuitionistic Fuzzy Expert System based Fault Diagnosis using Dissolved Gas Analysis for Power Transformer

  • Mani, Geetha;Jerome, Jovitha
    • Journal of Electrical Engineering and Technology
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    • v.9 no.6
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    • pp.2058-2064
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    • 2014
  • In transformer fault diagnosis, dissolved gas analysis (DGA) is been widely employed for a long period and numerous methods have been innovated to interpret its results. Still in some cases it fails to identify the corresponding faults. Due to the limitation of training data and non-linearity, the estimation of key-gas ratio in the transformer oil becomes more complicated. This paper presents Intuitionistic Fuzzy expert System (IFS) to diagnose several faults in a transformer. This revised approach is well suitable to diagnosis the transformer faults and the corresponding action to be taken. The proposed method is applied to an independent data of different power transformers and various case studies of historic trends of transformer units. It has been proved to be a very advantageous tool for transformer diagnosis and upkeep planning. This method has been successfully used to identify the type of fault developing within a transformer even if there is conflict in the results of AI technique applied to DGA data.

Integrated Magnetic Transformer for ZVS Phase Shift Full Bridge Converter

  • Li, Xin-Lan;Shin, Yong-Hwan;Won, Jae-Sun;Kim, Jong-Sun;Shin, Hwi-Beom
    • The Transactions of the Korean Institute of Power Electronics
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    • v.15 no.2
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    • pp.119-126
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    • 2010
  • An integrated magnetic (IM) transformer is proposed for a phase shifted full bridge (PSFB) converter with zero voltage switching (ZVS). In a proposed IM transformer, the transformer is located on the center leg of E-core and the output inductor is wound on two outer legs with air gap. The proposed IM transformer is analyzed by using the magnetic capacitor model. For reducing the core size, EE core is redesigned. The proposed IM transformer is experimentally verified on a 1.2 kW prototype converter. The converter efficiency with the proposed IM transformer is about 93 % at full load and its volume size can be reduced. It can be expected that the power density can be largely increased with the proposed IM transformer.