• 한국전기전자재료학회논문지
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• 제21권6호
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• pp.538-543
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• 2008

Nanostructured materials are attracting increased interest and application. Exciting perspectives may be offered by electrical insulation. Epoxy/Organoclay nanocomposites may find new and upgraded applications in the electrical industry, replacing conventional insulation to provide improved performances in electric power apparatus, e.g, high voltage motor/generator stator winding insulation, dry mold transformer, etc. In the paper work, the electrical and thermal properties of epoxy/organoclay nanocomposites materials were studied. The electrical insulation characteristics were analyzed through the permittivity characteristics. by analyzing the permittivity spectra, it was found that dielectric constant becomes smaller with increase frequency and becomes larger with increase temperature. This indicates restriction of molecular motion and strong bonds at the epoxy/organoclay nanocomposites. The morphology of nanocomposites obtained was examined using TEM and X-ray diffraction. It has been shown that the presence of polar groups leads to an increased gallery distance and partial exfoliation. Nevertheless, full exfoliation of clay platelets has not been achieved.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.748_749
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• 2009

21세기는 이산화탄소 저감에 대한 관심이 집중되어 다양한 에너지 효율향상 기술을 개발하는 환경의 시대에 살고 있다. 대용량 고압전동기는 운영에 따른 절연파괴가 발생할 경우 생산성에 영향을 크게 주기 때문에 기기 성능의 유지를 위한 적절한 상태의 유지보수가 중요하다. 따라서 효율적인 운영관리를 위해서는 절연상태 인자들에 대한 정확한 분석이 수행되어야 한다. 대용량 고압전동기의 절연상태를 예측하기 위해 상시 절연감시 시스템을 대용량 고압전동기에 적용하여 절연상태를 실시간으로 파악함으로써 기기 예방보전의 신뢰성을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.2033_2034
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• 2009

고전압회전기 고정자권선 절연물의 일반적인 운전조건에서 나타나는 열화특성은 많은 연구결과를 바탕으로 발전되어 왔다. 특히 고정자권선 절연물이 습한환경에서 운영되었을 경우 일반적인 절연물의 열화특성과는 다른것을 알 수 있다. 본 논문에서는 이러한 흡습특성에 대해 실제 산업현장에서 운영중인 고전압전동기 권선 절연물에서 나타나는 절연특성을 분석하고자 하였다. 이를위해 습한환경에서 운영중인 전동기를 선정하여 절연특성시험을 실시하였고 직류 및 교류시험전압결과에서 절연물의 흡습상태에 따른 고유의 절연특성결과값을 얻을 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 춘계학술대회 논문집 전기설비전문위원
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• pp.214-216
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• 2008

회전기 고정자권선 절연물은 전기적, 기계적, 열적, 환경적 열화요인이 단독 또는 복합적으로 작용하여 열화된다. 본 논문에서는 실제 산업현장에서 운영중인 고전압 전동기의 운영환경을 조사하여 건조환경에서 운영중인 전동기와 다습환경에서 운영중인 전동기에 대하여 절연진단시험을 실시하고 각 시험에서 도출된 절연진단인자를 비교하여 환경적 열화요인이 우세한 운영환경에 따른 절연물의 특성변화를 분석하였다.

• International Journal of Control, Automation, and Systems
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• 제3권spc2호
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• pp.376-385
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• 2005

The proliferation of technology has made global conduction of business increasingly dependent upon the availability of reliable power. As a result, alternate power systems are being installed and expanded to protect the broadening scope of critical electrical loads. Bus transfer restores designated critical loads to an alternate source when utility derived service becomes inadequate or goes out of service due to any contingency. This paper describes the practices, requirements and implementation of bus transfer of motor loads to an alternate source of power. A new high-speed automatic bus transfer scheme is proposed which includes the development of a new algorithm for determining the type of bus transfer required and the realization of the scheme by using modem protection devices and intra-substation communication facilities.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 추계학술대회 논문집 학회본부
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• pp.283-287
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• 1989

This paper presents a microprocesser based Self-Controller for a Permanent Magnet Synchronous Motor(PMSM), fed by voltage soure inverter. The proper operation of the PMSM can be ensured only if the stator current is always synchronized with the its Back-E.M.F. The use of incremantal encoder with high resolution makes it possible to design a Self-Control led P.W.M. inverter. The pulse ratios are controlled to reduce the torque ripple in the low-speed drive region. And during the operation, torque - speed characteristics are improved by the control of optimal load angle.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권12호
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• pp.751-758
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• 2004

This paper presents a new method to compensate the non-linearity for matrix converter drives using PQR instantaneous Power theory. The non-linearity of matrix converter drives such as commutation delay, turn-on and turn-off time of switching device, and on-state switching device voltage drop is modelled by PQR power theory and compensated using a reference current control scheme. The proposed method does not need any additional hardware and off-line experimental measurements. The proposed compensation method is applied for high performance induction motor drives using a 3 kW matrix converter system without a speed sensor. Simulation and experimental results show the proposed method using PQR power theory Provides good compensating characteristic.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 C
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• pp.1430-1432
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• 2001

In this paper, 200-class insulation system for form-wound stator coils is designed for form-wound stator coils is designed for AC traction driven with VVVF inverter. Model coils are made to embody all essential elements representing a winding insulation system and structure. Acceleration degradation for model coils is applied exposure to heat(235$^{\circ}C$). In order to investigate the condition of the coils and to determine their insulation reliability, high voltage test and the dielectric properties such as dielectric loss and capacitance are performed. Also, partial discharge measurement is investigated for internal defects.

• 한국철도학회논문집
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• 제9권3호
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• pp.277-281
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• 2006

The center pivot in the power car of KTX carries the traction force of the motor bogie to the carbody. The damage to the center pivot due to failure of swivel joint causes a serious hazard of the train. To prevent the hazard, information on the relative motion between bogie and carbody is necessary. In this paper, a method to measure the relative rotation of the center pivot is proposed and an actual test to verify the method and safety is conducted. The test results show that the rotation of the center pivot is within the allowable limit and the damage due to the relative motion doesn't take place.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(I)
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• pp.138-143
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• 2003

KHST(Korean High-Speed Train, 350km/h), composed of 7 cars that are 2 power cars, 2 motorized car and 3 trailer cars, has been developed and is under on-line test. To verify hte design requirements about the functions and traction performances of this train, KRRI(Korea Railroad Research Institute) decided to evaluate traction performances of the train during on-line test. For this purpose, such as torque, velocity, voltage and current, must be measured. BRRI has developed the measurement system that can be measured vast and various signals effectively. In this paper, we introduce traction performances of KHST. The traction measurement items are focused on the verification of motor block performances.