• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.11a
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• pp.465-470
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• 2008

This paper introduces experimental investigates of an electrical accident of the distributing cable termination with simulated badness construction. We prepared two termination kites, one is built-up type, the other is heat contraction type. Also, we manufactured cable termination that have simulated defect by badness construction and measured their insulation characteristics such as ac (35kV, 1min) and impulse (95kV, $1.2{\times}50{\mu}s$) withstand test. The influence of defects such as thickness and the gap between stress-con of housing and semi-conductor on insulating properties of the termination have been studied. The thickness decrease of insulator decreases ac breakdown strength. Dielectric breakdown traces of insulator that is damaged by knife displayed other shape. The gap of between housing and semiconductor deteriorates dielectric strength of insulator seriously.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.300-303
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• 1991

Sulphur-hexafluoride has extensively been used as an insulating gas of electric power equipment in substation for its high dielectric strength, non-toixity and non-flammable properties. But it is very expensive and is liquidizable under the condition of low temperature and high pressure. And it is very sensible to the locally high electric field strength. To resolve these problems, we studied 50% FOV and V-t characteristics of $SF_6-N_2$ mixtures under positive and negative lightning impulses using a 25mm rod-plane gap. 50% FOV of $SF_6-N_2$ 50% mixture was about 85% of pure $SF_6$ and it was known that $SF_6-N_2$ mixtures can be used as an economic substitution insulating gas for $SF_6$.

• 전기의세계
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• v.30 no.6
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• pp.357-365
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• 1981

When electronegative gas SF$_{6}$ is dissolved and charged with insulating oil, the effect caused in the process by electronegative characteristic is studied and also the pressure effect caused by electronegative SF$_{6}$ acting on the liquid-level is examined respectively. When inert gas Ar is used to find a pressure effect acting on the liquid-level, its effect on dielectric strength is considered in the experiment. With three kinds of impulse voltage different in the duration of wave front and wave tail, a brief experiment if carried out ot see the effects on the dielectric breakdown characteristic as the wave is changing; either if I$_{2}$ and SF$_{6}$ are added to the insulating oil, or if the oil pressure is increased by Ar the dielectric strength becomes great and the longer the duration of wave front is, the greater the increase of the breakdown voltage, because I$_{2}$ added by a small quantity brings about some hirderance in the formation of gas phase. Likewise, the greater the changed pressure is, the greater the incerase of the breakdown voltage. When SF$_{6}$ is charged, the electronegative characteristic is prevailing at the time of low balanced pressure, and the pressure effect at the time of high balanced pressure.ressure.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1639-1642
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• 1994

The severe conditions such as rated voltage of 800kV, gas pressure of $5kg/cm^2$ and rated lighting impulse withstand voltage of 2400kV were adopted for the design of spacers in the 800kV GIS to give a sufficient design margin. The design criteria on the maximum electric field strength of the center conductor and the insulator surface were established by considering the insulator surface characteristics, electrode area and surface effects in the unequal electric field strength of the given gap. The design parameters such as inter/outer envelope degree, thickness, inter/outer inserts, triple junction gap were determined by calculating the electric field using FLUX-2D program package and by referring to the published papers. The mechanical stress analysis was conducted on the feasible model spacers that showed good electric field distributions to confirm the sufficient mechanical design margin. The 800kV spacer designed as described above is now in the process of manufacturing.

• Journal of Korean Public Health Nursing
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• v.36 no.3
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• pp.323-333
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• 2022

Purpose: This study was conducted to identify factors of COVID-19 stress, impulsiveness, and family strength on suicidal ideation of public nursing officials in community health centers. Methods: This study was a descriptive analysis study the subjects of this study were a total of 145 public nursing officials from community health centers in Busan. The data were analyzed using IBM SPSS/WIN 23.0 version. Result: The result of the predictor analysis showed that the motor impulsiveness (β=.383, p<.001), workload (β=.222, p=.003), cognitive impulsiveness (β=-.205, p=.012), bond (β=-.169, p=.033). The regression model showed an explanatory power of 24.1%. Conciusion: it is necessary to increase impulse and stress control ability, and to adjust the workload. In addition, it is necessary to systematically guarantee a working environment where practical vacation can be used, but it may not be a realistic alternative in a disaster crisis such as COVID-19, so indirect alternatives such as reinforcing infectious disease experts, improving the work environment, and psychological support to prevent suicide in advance are required.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.6
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• pp.725-732
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• 2014

The silencer for the medium caliber gun was studied to reduce the propagation of gun-generated noise from the firing test range to the community. Three types of silencer were made to compare the reduction of sound pressure level and the effect of chamber volume and the exit angle to the reduction of sound pressure was considered. The structural analysis and measurement of pressure in the silencer showed that the structure is safe in terms of strength. The increase of recoil force to buffer must be considered in the development of silencer. The hypothesis test on the muzzle velocity for the existence of silencer showed that there are no difference at the significance level of 0.05.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.265-267
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• 1991

In this paper, we describe the development of 345kv OF cables to contain also the cable employing new insulation paper, PPLP (Poly propylene Laminated paper). The cables all show very excellent properties, especially PPLP cable has less the dielectric loss and better the impulse & A.C strength than the one employing the conventional paper. Therefore, according to use PPLP cable, it seems to be several advantages such as the compact of system, the increasing capacity, and the decreasing energy loss etc.

• Bulletin of the Korean Space Science Society
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• 2003.10a
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• pp.33-33
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• 2003

A clear bipolar (negative/positive) signature in the Ey component was observed by the Cluster satellite in the magnetotail during a sudden impulse (si) on October 11, 2001 (day 284). During the interval of the negative perturbation in Ey, the magnetic field strength in Bx, a dominant magnetic field component, was nearly constant. However, the amplitude of Bx was strongly enhanced during the positive Ey perturbation. We suggest that the observed E and B field variations are due to outward/inward plasma motions, associated with expanded and then compressed magnetopause variations. We also observed quasi-periodic geomagnetic perturbations in the Pc5 band (∼1-6 mHz) at the low-latitude ground station Kakioka (L = 1.25) following the si event. They were highly correlated with the magnetic field perturbations at Cluster in the magnetotail (Xgse = ∼12 Re). We show that the source of these perturbations is the quasi-periodic solar wind pressure variations moving tailward.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.10
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• pp.109-115
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• 2011

Apartments covered with a metal roof made from galvalume steel are prevailing due to their economic and technical advantages. The metal roof, however, has disadvantages in terms of the installation of air-termination system on it because of the slip thickness of the metal roof. In this paper, the impacts of the lightning current to a metal roof were verified experimentally with a short lightning impulse current (10/350[${\mu}s$]). Also, we developed various supporters of air-termination conductor for the metal roof and verified their excellent workability and economical strength through field application test.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.415-417
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• 1989

In this paper we introduce electrical and mechanical properties of PPLP, an insulation system of Cellulose/Extruded Polypropylene/Cellulose Paper, and characteristics of 345KV O.F cable employing the PPLP. This cable shows dielectric loss less than 50% and has excellent impulse breakdown strength higher than 17%, respectively, compared with those of the conventional cables. Accordingly, a more compact cable with reduced thickness of the insulation layer, which has remarkable profits in economics, has been developed.