• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 전력전자학술대회
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• pp.198-199
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• 2017

This paper proposed a new control method for supercapacitor (SC) to compensate the pulse load transient and enhance the power quality of dc microgrid. By coordinating the operation frequency, the supercapacitor is controlled to handle the surge current component while the low-frequency current component is dealt with by remaining sources in the system. Based on the state of charge and dc bus voltage level, the SC unit operation mode is automatically decided. Meanwhile, the dc bus voltage level indicates the power demand of the whole system; by regulating the dc bus voltage, the mismatch of power demand is covered by SC unit. The effectiveness of proposed method is verified by experiment prototype formed by two distributed generation and one supercapacitor unit.

• 전력전자학회논문지
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• 제12권1호
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• pp.56-64
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• 2007

최근 소형, 경량화 및 저가격화를 위해 절연형 고주파링크 승압 DC/DC 컨버터가 PCS (Power Conditioning System)에 많이 적용되고 있다. 하지만, 기존 전압형 컨버터 또는 전류형 컨버터가 적용된 고주파 링크 승압컨버터는 순환전류에 따른 도통손실과 변압기 누설인덕턴스에 따른 서지전압에 의해 여러 문제점을 내포하고 있다. 이들 문제들을 개선하기위해 새로운 2차측 LLC 직렬공진컨버터를 제안했고, 이에 대한 이론적 해석과 동작파형 및 시뮬레이션을 통해 800W급 시제품을 제작하여 실험결과에 대해 서술하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.326-327
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• 2006

The paper describes the development of arrester for 154kV class power station and substation. The arrester employs silicone insulating materials for Its housing, instead of the conventional porcelain housing. The sealing integrity is related to safe operation of surge arrester, the prime failure reason of porcelain housed arresters is moisture ingress. In this paper, the sealing integrity of polymeric surge arresters for ultra high voltage is investigated with moisture ingress test. The diagnostic techniques are discusses, including watt loss, partial discharge, AC leakage current, 1mA DC voltage and residual voltage.

• 전기학회논문지
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• 제64권1호
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• pp.196-200
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• 2015

The switching noise in the power electronics of the power conversion equipment (Power Conditioning System) for large energy storage devices are generated. Since the burst-level transient noise from being generated in the power system at a higher power change process influences the control circuit of the low voltage driver circuit. Noise may cause the malfunction of the control device even if no dielectric breakdown leads to a control circuit. To overcome this, this paper proposes the installation of an additional nano-surge protection device on the power supply DC output circuit of the battery management unit.

• Journal of Electrical Engineering and Technology
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• 제7권3호
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• pp.297-303
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• 2012

This paper presents the simulation results for the analysis of a lightning surge, switching transients and very fast transients within a thermal plant. The modeling of gas insulated substations (GIS) makes use of electrical equivalent circuits that are composed of lumped elements and distributed parameter lines. The system model also includes some generators, transformers, and low voltage circuits such as 24V DC rectifiers and control circuits. This paper shows the simulation results, via EMTP (Electro-Magnetic Transients Program), for three overvoltage types, such as transient overvoltages, switching transients, very fast transients and a lightning surge.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.637-639
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• 1999

ZnO varistors have been widely used to protect power system and electronic system against overvoltages based on their excellent nonlinearity. In order to increase their protection capability, ZnO varistors are chosen by several electrical parameters according to their applications, namely 1mA DC voltage, 1eakage currents, impulse residual voltages, withstanding capability to impulse surge, and energy absorption capability. But these Parameters have scattering properties due to the nonuniformity of electrical characteristics. In this study, the effect of the microstructrual nonuniformity on the surge absorption capability of ZnO varistors.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.644-647
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• 1999

The main objective of this paper is to design and test a new type of polymer ZnO surge arrester for DC power system of railroad vehicles. The rated voltage is 1500v direct current. The main research works are focused on structure design by finite element method, rat ing vol tape, temporary over vol tape and studies of character int ice of polymeric surge arrester .

• 한국정보통신학회논문지
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• 제11권10호
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• pp.1894-1898
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• 2007

본 연구는 산업체에서 널리 사용되어지고 있는 기존의 3상 AC-DC 컨버터에서 무게와 부피를 획기적으로 줄일 수 있는 고역율 3상 AC-DC컨버터를 제안하였다. 제안된 고역율 3상 AC-DC 컨버터는 LC 필터를 제거 한 상태에서 효율성과 다탕성을 검증함으로써 경량화는 물론 저 비용을 실현할 수 있게 된다. 또한 LC 필터를 제거하였음에도 불구하고 성능 면에서 볼 때 기존의 AC-DC 컨버터와 비슷한 성능을 얻을 수 있으므로 고전력 밀도 및 고역율이 요구되는 항공 우주 분야에 응용이 가능해 질 것으로 기대된다.

• Journal of electromagnetic engineering and science
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• 제5권4호
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• pp.193-196
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• 2005

The DC power-bus for the PCB is loaded with metal walls on its selected sides and is characterized electromagnetically. This is a novel concept of approach to mitigate the spurious resonance and finally signal integrity problems. In particular, the peak at DC, which is always in the way to secure parallel-plates' EMC, can be completely removed by the proposed method. Through the findings of this study, the effect of metal-loading of the power-bus will be presented along with the impression that the suggested technique can tackle the headaches of signal integrity, ground bounce, EMIs.

• 전력전자학회논문지
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• 제23권4호
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• pp.265-272
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• 2018

This paper proposes a new control method for the supercapacitor (SC) to compensate the pulsed load and to enhance the power quality of the DC microgrid. By coordinating the operating frequency, the SC is controlled to handle the surge current, while the low-frequency current component is dealt with by the remaining sources in the system. The operation mode of the SC unit is automatically changed based on the state of charge and DC bus voltage level. Meanwhile, the mismatch in the power demand is covered by the SC unit by regulating the DC bus voltage level. The effectiveness of the proposed method is verified experimentally by the prototype with two distributed generators and one SC unit.