• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.1166-1169
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• 2005

This paper describes a new transient voltage suppressor(TVS) with a low insertion loss and a high cut-off frequency to protect antenna circuit from transient voltages. Conventional protection devices have some problems such as a low frequency bandwidth and a high insertion loss. In order to improve these limitations, a coaxal type TVS, which consists of a gas tube is developed. The performance of the proposed transient voltage suppressor is tested by using a combination surge generator specified in IEC 61000-4-5 standard and by using a network analyzer of 40 MHz ${\sim}$ 5 GHz bandwidth. From the experimental results, it is confirmed that the proposed TVS has an enough protection performance in a low insertion loss and a high cut-off frequency.

• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.800-802
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• 1997

After flashover occurs on the overhead distribution line by lighting strokes(direct or induced), the power frequency arc current continues. If lightning flashover occurs on the overhead lines using covered conductors, the power frequency art current with fixed path overheats the conductor, and arc fusion fault can be occurred. There are two categories protecting or reducing methods of arc fusion faults caused by lightning stokes. - Reducing lightning flashover rate : G/W, LA, etc. - Protection by AFPD(Arc Fusion Protection Device) : power follow current interruption. This paper presents lightning surge phenomena on overhead distribution lines and protecting performance of arc fusion Protection devices to the lightning strokes nearby overhead line.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.563-566
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• 1989

Drive malfunction take many forms and every possible one must be protected against. Until recently a separate analog device was needed for each type of malfunction. In this approach to simplified, more reliable motor-circuit protection and control, a microprocessor's digital controller for motor control center simultaneously examine most of the possible sources of circuit trouble and has more efficent functions (sequence control,display) than the conventional motor control center. The result of standard surge tests provided a realistic evaluation of the surge withstand capability of equipment.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.153-154
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• 2013

고전압, 대전류를 갖는 뇌서지는 전원회로에 유입되었을 때 소자 파손 및 회로 오동작 등의 문제를 일으킨다. 이에 대한 보호대책으로 SPD(Surge Protection Device)소자와 스파크-갭(Spark-gap)을 주로 사용한다. 이 때, 기존의 스파크-갭은 뇌서지 유입 시 방전현상 이후에 발생된 스파크-갭의 패턴 마모로 패턴의 복구가 불가능하고, 불규칙하고 변칙적인 방전으로 인하여 발생되는 서지주요 예측경로의 소자 및 패턴 파괴와 같이 2차적인 문제를 발생시킨다. 이를 해결하기 위해 본 논문에서는 초기 유입 시부터 스파크-갭의 방전을 통해 에너지를 우회시킴으로서 전원회로의 뇌서지 부담을 줄여 전원회로의 안전성 및 안정적인 정상동작을 확보하는 대책을 제안하고, 스파크-갭의 구조에 따른 효과를 실험을 통해 검증한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.490-493
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• 1999

Due to the miniaturization of electrical components and assembles on signal and telecommunication circuits, transient overvoltages caused by switching operation or lightning surge has become more interesting concern to the field of electrical engineering. This paper describes the development of transient voltage blocking devices (TBDs) that can protect sensitive signal and telecommunication devices from overvoltages. Two kinds of TBDs are designed and tested by using a combination surge generator which can produce the standard impulse current of 8/20${\mu}$s 2.1kA according to the IEC 1000-4-5 standard. From the simulation and experimental reults, it is confirmed that the proposed TBD has an enough protection performance in low insertion loss and tight clamping voltage.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.285-288
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• 2009

WAN을 기반으로 하는 초고속 정보통신망이 구축되면서 컴퓨터를 기초로 하는 정보기술에 대한 의존도가 증가하고 있다. 그에 따라 컴퓨터를 비롯한 초고속 정보통신 설비 사고 가운데 뇌 서지에 기인하는 비중이 늘어나고 있다. 정보화 시스템의 일시적 기능 정지나 고장은 그 파급효과가 대단히 크고 경제적 손실이 막대하여 안정적인 서지 보호대책의 필요성이 높아지고 있다. 이에 뇌 보호 관련 규정이 KS C IEC 62305로 개정되면서 선택사항에 불과했던 내부 뇌 보호 시스템인 서지보호기 (Surge Protective Device 이하 SPD)가 필수사항이 되었다. 하지만 약 30%가 SPD 설치 후에도 서지로 인한 피해를 입고 있는 것이 현실이다. 이는 설치 후에도 SPD가 제대로 작동하는지의 동작 상태와 경년에 따른 SPD의 특성 변화를 알 수 없어 문제 발생 시 정확한 원인 분석이 불가능하여 효과적인 대책수립이 어렵기 때문이다. 따라서 기존 SPD 기술의 한계점을 극복하여 유입되는 외부 서지의 특성을 파악하고 고장 예측이 가능한 차세대 뇌서지 보호대책을 고려하여야 한다.

• Journal of the Korean Society of Safety
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• v.31 no.6
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• pp.19-24
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• 2016

One of key parameters on lightning protection system design of electric, information and communication system is grounding impedance. Earth impedance includes numerous information about earthing performance of grounding system. This paper suggests grounding impedance measuring device which is comprised of wideband current source, voltage and current measuring components. We used IQ Demodulation to measure more accurate phase difference of voltage and current. The range of frequency is up to 1 MHz that is IEEE defined as the range of lightning surge. We compared developed grounding impedance measuring device with existing one to test its performance, and we used grounding system while we implemented measurement and analysing by using fall of potential method IEEE Std.81 proposed.

• Journal of Advanced Navigation Technology
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• v.19 no.5
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• pp.395-402
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• 2015

This paper introduces the design details and test procedures of the lightning induced transient protection device for protecting the damage caused by indirect lightning strike on the computer mounted on the aircraft. Lightning induced surge voltage is bring a malfunction or damage to the aircraft electrical and electronic equipment, that is referred to indirect effects of lightning. In order to protect the electronic equipment on aircraft from the indirect effects of lightning, that is achieved by analyzing the effect on aircraft from lightning and protect design for each devices. In this paper, we introduce an indirect lightning strike level decisions, the protection circuit design method according to the chosen level through the RTCA DO-160G Section 22 category analysis and selection was performed in order to protect the damage caused by indirect lightning strikes in the protected equipment. In addition, we show the indirect lightning effects verification test performed to validate the designed protection circuits.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.400-407
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• 2016

The purpose of this study is to propose a useful method of solving the problem of thermal stability in surge protection devices (SPDs). First of all, the existence of the problem in the developed SPDs was confirmed by experiment. After analyzing the problem, a useful method of solving it is proposed and implemented. An experiment is performed to verify the performance of the implemented device. The results of this study are as follows; it is revealed that the problem of the thermal stability results from the varistor, one of the components in the SPD. A varistor with a built-in thermal fuse is applied to the SPD for the purpose of solving the problem. The experimental results confirmed that the thermal stability was improved by replacing the varistor. As a result of this study, the reliability of radar control units is enhanced and the probability of malfunction is reduced.

• Journal of the Korean Society of Safety
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• v.33 no.5
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• pp.21-27
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• 2018

The purpose of this study is to develop a SOP (Standard Operating Procedure) for a distribution board that can monitor the leakage current of a load distribution line in real time. The developed distribution board was fabricated by applying IEC 61439-1. It consists of the distribution board and an alarm device. The work process for making the distribution board was compliant with the KEMC (Korea Electrical Manufacturers Cooperative) regulations. And the AC distribution board range is 1,000 V. In addition, the voltage in DC is less than 1500 V. The distribution board receives a 3-phases and 4-wires power supply system and can supply power to the load of a maximum of 32 single or three phase distribution circuits. Also, leakage current measured on the power distribution board was used by sensors installed. The SOP of the developed distribution board consists of the installation standards for the short circuit alarm device and sensor, the surge protection device, switches and indication lamps, and other devices. The operation procedure was prepared so that each manufacturing step of the distribution board must be confirmed by the persons in charge of preparation, production, quality control and approval before moving forward to the next step.