• Journal of Auto-vehicle Safety Association
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• v.13 no.4
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• pp.73-80
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• 2021

Recently, Korea has established a plan for the supply of hydrogen vehicles and is promoting the expansion of the supply. Risk factors for hydrogen vehicles are hydrogen leakage, jet fire, and explosion. Therefore Safety measures are necessary for this hazard. In addition, risks in semi-closed spaces such as tunnels, underground roads, and underground parking lots should be analyzed. In this study, an explosion experiment was conducted on a hydrogen tank used in a hydrogen vehicle to analyze the risk of a hydrogen vehicle explosion accident that may occur in a semi-closed space. As results, the effect on the structure and the human body was analyzed using the overpressure and impulse values for each distance generated during the explosion.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.8
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• pp.1163-1168
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• 2013

The maximum allowable value of loop impedance($Z_s$) to secure the operation of overcurrent protective devices and the safety for indirect contact is a very important in TN-C-S system. The loop impedance is divided into inner loop impedance which consumer can adjust and external loop impedance($Z_e$) which only electric operator can adjust. Thus, an external loop impedance which limits to less than a certain value is a very important factor for human body protection against electric shock in TN-C-S system. The concept of loop impedance($Z_s$) is recently introduced to the domestic, the study about external loop impedance is yet insufficient. However, the study about the reference impedance as specified by the IEC 60725 standard to improve the quality and reliability of the power supply is being made. In this paper, reference value of external loop impedance($Z_e$) to meet domestic environment will be proposed by the nationwide measurement and statistical analysis.

• Journal of the Korean Society of Safety
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• v.29 no.2
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• pp.12-17
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• 2014

This paper is aimed to analyze the characteristics of simultaneous voltage, current and temperature signals for poor connection on electrical connector. In order to attain this purpose, detected were the current and voltage signals on electric wire with series arc, named arc signals, and also monitored were the changes of RMS, instantaneous value of waveform in time domain and temperature value with video. Two states are made normal state over $5kgf{\cdot}cm$ and poor connections state below $0.5kgf{\cdot}cm$ by screw gage. In the voltage signal case, the voltage drop was increased with which the current was increased. In the current signal case, poor connections at the time interval 1~4A all showed "shoulder", as distinct difference from the normal state shown waveform pattern. In the temperature signal case, poor connections are twice at 1A and five times at 4A in the normal state. The temperature continues insulation of electrical wiring and connector can be carbonized. The results of this study will be effectively used in developing the preventive devices and system for electric fire by poor connections.

• Journal of the Korean Society of Safety
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• v.19 no.1
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• pp.60-65
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• 2004

The PVC insulated flexible cords are used mainly as power supply cords of electric appliance. This electric wire is a stranded wire consisted of dozens of strands. In case stranded wires are disconnected by mechanical stress, it weakens electrically. Finally, the over current flows through stranded wires, and electrical fire occurs. In this study, we analyzed the melting properties of strands by over current, such as melting process, melting current and melting time. And we analyzed that quantity of heat for melting, a cross sectional structure, and surface structure by optical microscope and SEM. As analysis results, melting time decreased as melting current increased. And quantity of heat for melting was low, too. From the cross sectional structure of melted wire, when a melting current low and melting time long, it was found that the dendrite structure grew. However, the dendrite structure is hard to grow because growing time is not enough when a melting current high and melting time short.

• Journal of the Korean Society of Safety
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• v.34 no.5
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• pp.22-30
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• 2019

In 2018, overload, overcurrent, insulation aging, and a contact failure caused 659 electric fires. There is almost no failure of electrical socket outlets during their manufacturing or installation period. After several months or several years, overload or overcurrent of electrical socket outlets leads to a contact failure or short circuit which causes an electric fire. Therefore, this paper analyzed for thermal characteristics based on a current value and the change in insulation resistance along with a temperature rise caused by electrical socket outlets and the state of laboratory use in workplaces. As a results, regarding the thermal characteristics based on the current value of each installation year, a temperature increase was related to a current value, an installation year, and whether the contact unit is corroded. Insulation resistance began to decrease when a temperature increased to a certain level. With a lapse of installation year, the temperature at which insulation resistance began to decrease was lowered. This paper can be applicable for the survey data about electrical socket outlet induced fire accidents and management guidelines.

• Nuclear Engineering and Technology
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• v.52 no.5
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• pp.956-963
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• 2020

Dose optimization for Radioactive Occupational Personal (ROP) is an important subject in nuclear and radiation safety field. The geometric environment of a nuclear facility is complex and the work area is radioactive, so traditional navigation model and radioactive data field cannot form an effective environment model for dose assessment and dose optimization. The environment model directly affects dose assessment and indirectly affects dose optimization, this is an urgent problem needed to be solved. Therefore, this paper focuses on an environment model used for Dose Assessment and Dose Optimization (DA&DO). We designed a multi-layer radiation field coupling modeling method, and then explored the influence of the environment model to DA&DO by virtual simulation. Then, a simulation test is done, the multi-layer radiation field coupling model for nuclear facilities is demonstrated to be effective for dose assessment and dose optimization through the experiments and analysis.

• Proceedings of the KIEE Conference
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• 2007.04b
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• pp.10-15
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• 2007

For the introduction of the electricity of the special design and supervision system to Protect the faulty-workmanship of the electricity equipment and to reserve the electricity safety, last 1995 "Electricity Technology Management Act" were carried out enactment. March 2002, we introduced the pre-Qualification system that is selected the competent company about the electricity design and supervision service over so much capacity which is ordered by the Public institution such as the nation, local autonomous entity, government investment institute and so on. December 2005, the electricity equipment over so much capacity was taken the housing construction plan's approval by the housing act in case, the municipal or district governor with the authority to approve who selected the electricity supervision company according to the pre-Qualification system. Due to the introduction of the system, we could expect the rights and interests increase of the consumer by eradicating dumping of the close relationship between supervision company and the builder, reduction and concurrent position of the supervisor, according to confirm the quality of the electricity equipment and electricity safety. In spite of introducing of the system, the problems occured as reducing the electricity designer's task range compared with different field, modifing the supervisor's rank system rationally, because of researching about the electricity design and supervision technique lacks. Also, KEEA(Korea Electric Engineers Association) manage the caller of the electricity design and supervisor(company or people), but the problems occured as opening to the public about the curler management, introducing automatic bidding system and We need the solution plan about this. Consequently, we consider the present situation of the domestic and outside and problem about the electricity design and supervision system in this paper, try to present rational operation plan through this.

• Journal of Korean Institute of Fire Investigation
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• v.10 no.1
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• pp.47-57
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• 2007

If it were the occurrence of fire by electricity with the rapid growth of economy, it would be serious damage for nation that effect human life and properties. To prevent electrical fires, it was basic countermeasure that make detail statistics classified by the source, place etc. with examining correct cause of fire. In this paper, we analuzed the present condition of fire occurrence of the lastest ten years and classified fires by the source, place, month in 2006. In addition our corporation staff execute in-depth and professional research on the actual state of electrics fire by visiting fire stations fire of the whole country for 8,554 electric fires in 2005. I expect this thesis to be used for preventing electric fires and providing a stepping stone on correct production of fire statistics.

• Proceedings of KOSOMES biannual meeting
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• 2018.06a
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• pp.194-194
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• 2018

• Proceedings of the KIEE Conference
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• 2008.09a
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• pp.308-309
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• 2008

태양광발전산업은 21세기의 청정에너지 및 대체에너지로 주목받으면서 그 관련 산업이 매년 큰 성장세에 있다. 그러나 태양광발전시스템의 DC계통 사고 보호에 대한 안정성이 확보되지 않고 보급 설치되므로 이에 대한 대책이 필요한 것이 현실이다. 본 논문은 DC계통사고 등의 문제점을 지적하고 그 대책을 연구하여 계통의 안전성 확보와 인체 감전보호론 목적으로 연구하였다.