• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.3
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• pp.494-500
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• 2008

This paper presents the analyzed result of the series arc fault current by using the discrete wavelet transform. The series arcing is caused by a loose connection in series with the load circuit. The series arc current is limited to a moderate value by the resistance of the device connected to the circuit, such as an appliance or a lighting system. The amount of energy in the sparks from the series arcing is less than in the case of parallel arcing but only a few amps are enough to be a fire hazard. Therefore, it is hard to detect the distinctive difference between a normal current and a intermittent arc current. This paper, presents the variation of the ratio of peak values and RMS values of the series arc fault current, and proposes the novel series arc fault detecting method by using the discrete wavelet transform. Loads such as a CFL lamp, a vacuum cleaner, a personal computer, and a television, which has the very similar normal current with the arc current, were selected to confirm the novel method.

• Journal of Electrical Engineering and Technology
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• v.8 no.1
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• pp.176-182
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• 2013

In this study, we examine the tracking happen in a polyvinyl-chloride-sheathed flat cord (PVCSFC), which is widely used as a distribution cord. The study classifies the bridge current via the formed conductive paths during tracking in the PVCSFC. Further, it attempts to distinguish the characteristics of heat generation and heat transfer by kind of bridge current. When the PVCSFC is in the static state, the bridge currents flow only through the electrolyte bridge. In the case of the carbonized PVCSFC, the bridge currents flow through one or more conductive paths. One is the electrolyte bridge, the other is the bridge that is consisted electrolyte and carbonized insulation. Currents flowing through different conductive paths have different heat generation and transfer characteristics. As the bridge current flowing in the conductive path consisting of electrolyte and carbonized insulation increases, the temperature difference between the surface of the PVCSFC and ambient air also increases correspondingly.

• Fire Science and Engineering
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• v.29 no.6
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• pp.33-39
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• 2015

In this paper, a numerical experiment was conducted to find out the optimal location of electrical heat trace for anti-freeze of water inside the CPVC pipe for fire protection. The unsteady incompressible Navier-Stokes equations coupled with energy equation were solved. Since the conduction equation of pipe was coupled with the natural convection of water, the analysis of conjugate heat transfer was conducted. A commercial code (ANSYS-FLUENT) based on SIMPLE-type algorithm was used for investigating the unsteady flows and temperature distributions in water region. From the present numerical experiment, it has been found that the vector field of water inside the PVC pipe is opposite to the case of steel because of the huge difference of material properties of the two pipes. Furthermore, it was found that the lowest part of the pipe was an optimal position for electrical heat trace since the minimum water temperature of the case was higher than those of the other cases.

• Journal of the Korean Society of Safety
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• v.30 no.3
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• pp.26-31
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• 2015

This paper describes the characteristics of voltage drop and thermal for poor connection on electrical connector of circuit breaker in control box of small size pulverizer. In order monitor, we did the changes of RMS in voltage and temperature value with video and made normal state over $2.5N{\cdot}m$ and poor connections state below $0.2N{\cdot}m$ by screw gage. In case of voltage signal, the voltage drop was increased when the current was increased due to poor connections. In case of temperature signal, the temperature difference indicates ten times at 5A and fourteen times at 15A in the normal state. According to increase thermal energy, the insulation of electrical wiring and connector of circuit breaker can be carbonized. The results of this study will be useful to the development of preventive devices and system for electric fire by poor connection at small size pulverizer.

• Journal of the Korean Society of Safety
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• v.32 no.1
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• pp.41-46
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• 2017

In this paper, from making an electrical fire which is thought to be the most damaging among potential dangers as a top event, minimal cut sets (MCS) about it were analyzed. For this, components of a power substation were classified into 15 items. Failure rates and modes were extracted based on Korea Electrical Safety Corporation, IEEE Gold Book, and RAC. To analyze the top event (an electrical fire), main events were assorted into "safety devices for overcurrent" and "ampere meter of detecter". Failure of components was divided into failure of VCB, COS, and MCCB. A fault tree was composed of 3 AND gate, 5 OR gates and 17 basic events. Overlapped events among the basic events are things which occur from relevant components. They were attached to the tree by distinguishing identifiers. In case of FT, two minimal cut sets of "IO_METER", "MF_METER", "DO_MCCB" and "IO_METER", "MF_METER", "DO_VCB" take 46% of electrical fires. Therefore, about basic events which are included in the top two minimum cut sets, strict control is necessary.

• Fire Science and Engineering
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• v.20 no.1 s.61
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• pp.43-49
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• 2006

In this paper, we are studied on the temperature characteristics and fire progress of an incandescent electric lamp at 220V/100W. In the case of stationary state, the ignition possibility of the incandescent electric lamp due to the heat generation was low because the temperature was measured at $161.9^{\circ}C$ the temperature was increased at $538.1^{\circ}C$ in the airtight chamber, but it does not generated the fire because the oxygen was not exist in the airtight chamber. When the lamp is broken, the filament of lamp was melted in the air. The gas of lamp interior spurted to the weakest part by external flame. Thus, the incandescent electric lamp is high possibility of fire when oxygens from airtight space. Also, it is known that the possibility of ignition is very high if combustion materials(sawdust) exists on surrounding. These experimental results will be utilized for the data in the investigation electrical fire cause.

• Journal of the Korean Society of Safety
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• v.38 no.1
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• pp.34-41
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• 2023

In this study, S food manufacturing business located in Chungbuk was selected as the subject, and the transition in insulation resistance in major electrical equipment used in this food manufacturing business was analyzed for 4 years (2018-2021). It was confirmed that the insulation resistance decreased over time for all 18 electrical facilities. Insulation resistance changed due to environmental influences such as load characteristics and ambient temperature. Particularly in the case of the food manufacturing industry, it was confirmed that the decrease started after 2 years, although it varied depending on equipment and environmental influences. Furthermore, it was confirmed that management through predicting the management cycle of electrical equipment is possible by deriving a regression equation through regression analysis of insulation resistance measurement values.

• Proceedings of the KIEE Conference
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• 2008.09a
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• pp.301-304
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• 2008

In this paper, we study from of flowing leakage current in electrical installation. Leakage current is expressed by a resistivity leakage current($I_{gr}$), a capacitive leakage current($I_{gc}$), an inductivity leakage current($I_{gl}$). General Zero Phase Current Transformer (ZCT) detect a leakage current($I_{g}$) that are conjoined resistivity leakage current and capacitive leakage current. In case $I_{gr}$ is big than $I_{gc}$, there is no singular problem in leakage current detection of system. But, in case $I_{gc}$ is big than $I_{gr}$, earth leakage breaker can not prevent accident effectively. Can lower electric leakage perception current to 5 mA if apply resistivity leakage current detecting circuit. We can achieve prevention of electricity disaster spontaneously.

• Journal of the Society of Disaster Information
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• v.8 no.4
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• pp.362-375
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• 2012

Tourist hotels are equipped with facilities such as accommodation and restaurants, exercise, recreation. Unspecified guests, visitors and management of tourist hotels are very vulnerable on the casualties and property losses due to fire peril exist. In this study, we analysis that the fire statistics status of tourist hotels from 2001 to 2010. And the 15 cases of a large hotel fire are reviewed. The total number of fires on hotel are consist of a hotel rooms fire(33.2%), a restaurant kitchen fire(11.8%). And the major causes of the fire are an electrical fire (40.8%), a cigarette fire (14.5%) and a hot-work fire (9.2%). In case study, the fire wall defect and combustible materials are major fire loss causes for 10year. Each tourist hotels are needed a development of suitable fire risk management and a field operations. A hotel is required an active fire risk management on a preventive inspection, an education and training, and a preventive maintenance. It is necessary that a fire wall maintenance to prevent of the spread of a fire and a sprinkler installation of whole area to protect fire. And it is very important an emergency response for evacuation of guest, and operate emergency procedures on a fire or emergency situation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.8
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• pp.1184-1191
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• 2013

Probability of ignition due to arc-fault and energy of the arc-fault for the case of applying serial arc-fault interruption time of 120 V defined in UL 1699 to the voltage of 220 V of domestic condition and also for the case of applying it to the HIV wire type are analyzed. It has been confirmed that when the arc-fault occurs under 5 A, 10 A, and 20 A. Probability of ignition for the three different current conditions is 0.74(74%), 0.48(48%), and 0.32(32%) respectively for respective interruption time within 1 sec, 0.4 sec, and 0.2 sec. We discover that when we apply the same arc interruption time for 120 V defined in UL 1699 to the domestic environment of 220 V. The probability of ignition increases from 1.5% for 120 V condition to as much as 74% for 220 V condition. Conclusively, if we apply the standard for the serial arc-fault interruption time defined in UL 1699 for 120 V to the domestic condition of 220 V, the fire prevention effect of electric fire due to arc-fault equal to that of UL standard of 120 V can not be achieved.