• Proceedings of the KSR Conference
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• 2008.06a
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• pp.596-602
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• 2008

Recently, there are increasing social needs for safe operation of trains and comforting for passengers. But lightning surges are responsible for serious disturbances such as damage, permanent degradation or temporary erratic operation of sensitive electronics circuits and systems. The purpose of this paper is to identify the requirements for Surge Protective Devices(SPDs) used in protecting railway signalling system. In this paper, we describes tests and requirements which establish methods for testing SPDs and determining their performance.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.278-281
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• 2001

본 연구에서는 철도 시스템에서 발생할 수 있는 서지관련 전자기장해 현상을 고찰하고, 철도 시스템용 서지보호장치가 갖추어야 할 기본 성능을 검토하였다. 서지보호장치 관련 철도규격을 국제규격과 비교 검토한 결과 성능평가 항목에 있어서 개선사항을 발견하였다. 이러한 사항들을 토대로 하여 철도규격의 개정방안을 제시하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.6
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• pp.1253-1259
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• 2005

This paper dealt with the development of surge protection devices (SPDs) that can protect high speed computer network devices from overvoltages caused by switching operations or lightning surges. The designed SPD is a form of hybrid circuit which is composed of a gas tube having large current diverting capability, high response bi-directional avalanche diodes, and fast recovery diodes to reduce insertion loss on high frequency domain. Surge protection and signal transmission characteristics of the fabricated SPD was tested according to the international standards, IEC 61000-4-5 and IEC 61643-21. From the test results, the SPD is satisfied with the international standards and the high cut-off frequency was 204 MHz. Also, the SPD showed a good performance without an insertion loss on a field test of 100 Mbps class Local Area Network.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1038-1043
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• 2010

According to the korea standard (KS)'s definition through 'KSC IEC 61643-1(2007), A SPD(Surge Protective Device) is an appliance designed to protect electrical devices from voltage spikes and the principal components used to reduce or limit high voltages can include one or more of the nonlinear components. 4 type of those nonlinear components are utilized in accordance with korea standard's IEC regulation. The SPD is installed the place(in and out side of installation for protecting damage due to the inflow of light surge) which we need by combination of nonlinear components. In this study, the analysis based on the characteristics of SPD from PF track circuit are discussed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.1
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• pp.35-41
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• 2007

Recently, there are increasing social needs for stable supply of electric power and securing high quality of information and communication services. In this work, to propose the effective protection countermeasures of information-oriented equipments against lightning surges, the protection effects of surge protective devices(SPDs) were experimentally investigated using actual-sized test circuits in various installation conditions. As a result, it was found that the protection effect of SPDs is quite different depending on the factors, such as the grounding system of power source, numbers of branch circuits, wiring method of grounding leads, and etc. In case of installing SPDs for information-oriented equipments, including all electric power lines and communication lines, the common grounding should be the most effective. Wiring method containing grounding leads with power lines in metal conduit is suitable to improve the surge cutoff performance of SPDs.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.3
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• pp.149-156
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• 2004

This paper deals with the effective protection method for the household electric appliances against lightning surges invading from the Power lines. Direct or induced lightning is the main cause of the breakdown of household electric appliance. The most effective protection method is to install SPDs(surge protective devices) at household electric appliances. If SPDs were not installed at most household electric appliances, it is necessary to install SPDs on the mains. Therefore the propagation aspect and protection methods of lighting surges coming into household electric appliances through the mains was experimentally investigated. The in actual-sized test circuits results of protection method for 8 household electric appliances including computer monitors and TV set could be summarized as follows: The breakdown characteristics of household electric appliances from lightning surges were significantly changed with the their input impedance. Namely, the types of input impedance are classified into infinite, resistive or inductive impedances. Especially, the monitor for computer with inductive input impedance from lightning surges was relatively weak against lightning surges. It was confirmed that the self inductance of branch circuits on the mains have protection effect for household electric appliances against lightning surges invading from the power lines. Also the varistors installed at cabinet panel or circuit-breaker were more effective than multi-tap outlet with varistors. When installed varistors in cabinet panel and multi-tap outlet together, the surge protection effect is much more excellent in technical and economical aspects.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.298-302
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• 2005

This paper presents the protection effect of SPDs according to installation conditions. To develop the effective protection countermeasures of information and communication equipments against lightning surges, actual-sized experiments in relation to the protection effects on the installation positions of surge protective devices(SPDs), the length of branch circuit the materials and long of conduit were conducted. The best method for protecting the electronic equipments from surges is to install the SPD at the front point of the devices to be protected. The installation method of the metal conduit bonded with common ground conductor were more effective than that of the PVC conduit.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.8
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• pp.22-29
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• 2006

According to the recent revision of KS on the basis of the IEC, equipotential grounding systems has been come into focus and the use of surge protective devices(SPD) has been increased radically in order to operate the power system stably. $Z_nO$ varistor with non-linear resistance, which has an outstanding voltage-current(V-I) characteristic, is mainly used in power system to limit surge voltage and divert surge current. $Z_nO$ varistors are packaged several types based on the circuit assembly to be connected to a.c. power line. When the user assemble the $Z_nO$ varistors into parallel or series circuit package, there are my things to be taken into consideration including functions and thermal stability because they are directly related to the safety. We compare stabilities of each assembly type by measuring residual voltage, discharge current, leakage current and surface temperature concerned to the protection performances between a single device with a 40[kA] of current capacity and parallel or series circuits type of varistor package.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.3
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• pp.39-45
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• 2010

This paper deals with investigation on the spot for grounding systems of buildings based on international standards at construction sites. The investigation was carried out for grounding method, grounding type, shape of grounding electrode, grounding for a lightning protection system, continuity of steelwork in reinforced concrete structures, etc. The investigation on the spot was performed by a researcher and engineer with over fifteen years of industry experience all over the country. As a result of the investigation on the spot in 13 buildings, common grounding and structure grounding methods were dominant. The safety improvement methods include installation of equipotential bonding conductors for the connection to the main earthing terminal, equipotential bonding conductors for supplementary bonding, use of Surge Protective Devices (SPD), and safe connections between earthing conductors and the rebar.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2025-2026
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• 2008

This study aims to analyze the features of malfunction of an SFC that helps maintain the frequency of static rotation during the operation of a gas turbine in power plants where power generators and controllers have such a complicated structure as a nerve system, by using electric interference with peripheral devices and maintaining acquired data efficiently. Also, in order to track the possibility of malfunction by various surges and noises which may occur in the process of inserting an SFC during the operation of a gas turbine and to prepare protective measures for the possibility, the study intends to offer data for developing a surge protector suited to the features of a section that is supposed to incur the possibility of malfunction.