• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1900-1902
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• 2000

In this paper, the temperature distribution and thermal stress analysis of mold transformer for power distribution system is investigated by FEM. Filler type epoxy is applied for good cooling effect in mold transformer.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 C
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• pp.939-942
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• 1998

This paper presents the process on the construction for the remote distribution pole transformer monitoring system. Especially, this system uses CATV cable as communication media which is located in KEPCO's main distribution line. It has four major components such as sensor for measuring secondary voltage and currents of distribution transformer, RF modem for data modulating/de-modulating, communication media for sending/receiving of data, and pc server for monitoring the results of sensing or computing information. This paper also describes the configuration of these each component's configuration and its functions.

• 전기학회논문지
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• 제61권10호
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• pp.1536-1541
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• 2012

The study analyzed problems by iron core structure of the three phased transformer on asymmetric three phase lines, which included line disconnections, ground faults, COS OFF, and unbalanced loads on the power distribution system. In particular, by analyzing PT combustion cases within the MOF, the study was able to analyze the combustion cause of the core-type transformer and its effect on the system, conduct simulations and practice demonstrations on the characteristics for each iron core structure of the three phase transformer using PSCAD/EMTDC, and suggest measures to prevent the combustion of the core-type transformer.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전력기술부문
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• pp.346-348
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• 2002

This paper analyze spectrum of vibration-frequencies to reduce noise level of distribution transformer. Using loading back method on same condition of a real load to grasp the effect of core and winding which are caused by the transformer vibration. we were measured the vibration-frequency by varing applied voltage and load current of a transformer. The major cause of a transformer vibration is occured by the harmonic effects, and was identified that the vibration is less influenced by the coil. As the result of this paper, comparing the transformer with some isolated material with the general transformer the transformer with some isolated material could reduce spectral amplitude of vibration-frequencies.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
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• pp.6-8
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• 2001

This paper covers general recommendations for top-oil temperature rising of mineral-oil-immersed power distribution transformer rated 100kVA and less, manufactured in Korea. In order to analyze the top-oil temperature rising due to the distribution transformer loading we performed experiments for oil-immersed distribution transformer, manufactured in domestic at KERI(Korea Electrical Research Institute) from December 2000 to May 2001. The magnitude of loading were changed, and the top-oil temperatures for each time were measured. Finally, we present the overload criteria of distribution transformer for summer and winter season in domestic. respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
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• pp.371-373
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• 2001

In this paper, we present 2-step load cycle for daily load curve of up to and including 100kVA distribution transformer in domestic. Daily load patterns are classified by two methods dependent upon possession information. In case we possess daily load profiles make use of K-mean algorithm and in case we have not daily load profiles, make use of customer information of KEPCO. As the parameters of the load pattern classification, we use are daily load profiles and customer information of each distribution transformers. Data management system is used for NT oracle. We can present peak load magnitude, initial load magnitude and peak load duration for daily load patterns by 2-step load cycle for daily load curve of up to and including 100kVA distribution transformer in domestic. We think that this paper contributes to enhancing the distribution transformer overload criterion.

• 한국전기전자재료학회논문지
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• 제23권10호
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• pp.798-803
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• 2010

This paper describes the characteristics of electromagnetic wave propagation in power transformer. A transformer which is similar to 154 kV single phase on-site transformer unit was provided for the purpose of the experiment. The 12 dielectric windows on the transformer enclosure to install UHF (ultra high frequency) sensors and the full scale mock ups of winding and the core were also equipped in the transformer. Every sensors to be installed to the transformer was tested and verified whether they show same characteristics or not before the experiment. A discharge gap which was used as a PD (partial discharge) source moved to several necessary locations in the transformer to simulate dielectric defects. Propagation times of electromagnetic wave signal from PD source to sensors decided by the routes of both reflection phenomenon and diffraction phenomenon were compared each other. The experimental results showed propagation route of the PD signal makes an effect on the frequency spectrum of front part of the signal and the magnitude of the signal and propagation time of the signal when the signal is captured on the sensor.

• 전기학회논문지
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• 제58권8호
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• pp.1479-1484
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• 2009

The introduction of the large transformer due to the large power demand has increased the fault current in power distribution system. The increased fault current can exceed the cut-off ratings of the circuit breaker. As the methods to solve this problem, the superconducting fault current limiter(SFCL) has been notified. However, the limited fault current by SFCL affects the operational characteristics of the protective device such as overcurrent relay. Therefore, the selection of the proper impedance for the SFCL is required to keep overcurrent relay's protective coordination with the SFCL when a large transformer is introduced into the distribution system. In this paper, the SFCL's impedance for protective coordination was investigates in that a large transformer is introduced.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기물성,응용부문
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• pp.245-247
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• 2001

In this paper, the temperature distribution and thermal stress analysis of 50kVA pole mold transformer for power distribution are investigated by FEM program. The temperature rise test of designed mold transformer is carried out and test result is analyzed compare to simulation data.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전력기술부문
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• pp.139-141
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• 2005

For the reliable evaluation of the distribution and power transformer no-load loss measurement, measurement uncertainty of the transformer measuring system, consisted of current transformer, potential transformer and power metering equipment is required. In this paper, we describe the uncertainty of transformer measuring system based on ANSI/IEEE C57.12.90.