• Journal of the Korean Society of Safety
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• v.19 no.2
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• pp.26-33
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• 2004

This study presents a hazard assessment of the human body exposed to electic shock considering various parameters which affect severity of the electric shock. The present study has two research objectives; one is no analyze hazards of the human body by the elctric shock both on the ground and in the water. The other is to understand the mechnism of the electric shock. In order to achieve these objectives the hazard of shock is estimated by comparing with physiological effects of electric curren througn the human body according to variation of shock parameters of shock circuits. The shock parameters adopted in this paper consist of body resistance, resistance of protective equipment, ground resistance, shock duration, depth of gound surface layer, relection factor, permissible touch voltage, body current and body voltage. Besides, safety standard determining hazard degree of the human body is introduced. And hazard of the human body due to the electric shock is quantitatibely assessed in consideration of data obtained by the method suggested herein, and final results are presented and discussed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.10
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• pp.68-73
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• 2006

As in the measurement of ground resistance by using the 3 point fall-of-potential method, it is known that the distance of current electrode should be at the point of showing the plateu on the potential curve. But the problem is that it my be practically impossible to meet the condition in actual sites. For solving such a situation, this paper provides the least distance of current electrode according to the analysis for the test-field measurement showing that it is feasible to measure the ground resistance in the two in current electrode distance as the length of driven-rod type electrode and the some district length of mesh electrode.

• Journal of Korean Port Research
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• v.14 no.4
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• pp.463-473
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• 2000

Reinforcement with geotextiles have been used in the foundation soil to enhance the resistance of embankments to avoid failure through excessive deformation or shear in the foundation. It is improtant to know the amount of the strain and the displacement of buried geotextiles for the verification of the reinforcement behaviour. Full scale trial constructions were performed to check the deformational characteristics of the polyester(PET) mat which was used for the embankment reinforcement. Many instrumentation equipments including surface settlement plates, profile gauges and inclinometer casings were installed to observe the behaviour of the soft ground due to the soil embankment. 60 electrical resistance strain gauges and 9 vibrating wire LVDTs were installed 세 measure the deformation of the polyester mat. Results of various tests and geotextile, waterproofing and protection from the hazard environments were introduced. The proposed instrumentation method was effective for the monitoring or the geotextile behaviour. The direct attachment of electrical resistance strain gauges on the gertextile mat was able to measure small changes of the strain of geotextiles. At the end of the 5 month monitoring, 54 of 60 (93%) strain gauges and 7 of 9 (78%) displacement transducers survived all perils of the compaction impacts and the humidity. And the tensile strain of grotextiles increased as the ground displacement became larger. Though the observed strain of mats under the 3m high embankment load was less than 1%, the magnitudes of the strain according to the mat spreading method were different from each other.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.284-287
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• 2006

In this paper variety test results were discussed regarding to the ground potential increase. The tests conducted with a joint box simulating leakage point having an insulator fault. Inside the joint box three-phase cables and one neutral line were connected and the insulator at jointed part was peeled from the one of three-phase cables. The potentials around manhole cover were measured with the variation of manhole material, ground resistance and water resistance when the manhole was flooded. The potentials induced by an electric leakage were drastically decreased with increasing the distance from the leakage location and with less ground resistance.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.6
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• pp.505-510
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• 2001

We simulated the current limiting characteristics of a resistive superconducting fault current limiter (SFCL) for a single line-to-ground fault in the 22.9 kV system. The transient current during the fault increased to 6.33 kA, 5.80 kA and 3.71 kA without SFCL at the fault angles 0$^{\circ}$, 45$^{\circ}$ and 90$^{\circ}$, respectively, a resistive SFCL limited effectively the fault current to 2.27 kA in a half cycle without any DC components. The maximum quench resistance of an SFCL, 16Ω was suggested to be appropriate to limit the fault current in the 22.9 kV distribution system, considering the operating cooperation of a protective relay and the current limiting performance of an SFCL.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.3
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• pp.162-167
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• 2004

The scale model grounding systems to study the behavior of grounding system in uniform soils have been designed and fabricated. Constructional details and instrumentation have been discussed. To verify the accuracy of the results obtained from the experimental tests, they have been compared with computer calculation results. Also, in order to assess the effectiveness of bonding two grounding systems, grounding grid conductors which were downsized as a scale factor of 100:1 were analyzed by using the scale model method. A profile of GPR(Grounding Potential Rise) of each case was measured. The scale model grounding system presented in this paper can be valuable tool to analyze the ground potential profile and ground resistance of practical grounding system.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1256-1263
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• 2010

Suction Drain Method is soft ground improvement technique, in which a vacuum pressure can be directly applied to the Vertical Drain Board to promote consolidation and strengthening the soft ground. This method does not require a surcharge load, different to embankment or Preloading Method. In this study, ground improvement efficiency of suction drain method was estimated when duplex loading pressure with vacuum and pressure. During suction drain method process, surface settlement and pore pressure were monitored, and cone resistance test as well as water content were also measured after the completion of Suction Drain Method treatment.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.11
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• pp.91-97
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• 2011

In Korea, characterized in most cases by limited area or high earth resistivity, it is likely to design narrow distances between grounding conductors, with a view to keeping ground resistance and touch voltage below the safety margin values. A new grounding method is suggested, making use of double meshes, to lower touch voltage in a confined area, since it is difficult to lay the plugs under the ground with narrow gaps between them on a limited site. For the presentation of a new model, the suggested grounding system has been analyzed and studied in ground resistance, touch voltage and step voltage, using IEEE Std. 80 calculations and computer simulations.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.10a
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• pp.69-72
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• 2008

This paper presents the transient and conventional grounding impedance behaviors of large grid grounding system associated with the injection point of impulse current The measurement methods consider two possible errors in the grounding-system impedances: (1) ground mutual resistance due to current flow through ground from the ground electrode to be measured to the current auxiliary, (2) ac mutual coupling between the current test lead and the potential test lead The test circuit was set to reduce the error factors. The transient grounding impedance depends on the rise time and injection point of impulse current It is effective that grounding conductor is connected to the center of the large grid grounding system.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1874-1876
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• 2000

In this paper, the effects of the positions of the current probe on the measurements of the ground resistanc, and potential gradients with fall-of-potential method are described, and the testing techniques to minimize the measuring errors are proposed. The fall-of-potential method is theoretically based on the potential and current measuring principle and the measuring error is primarily caused by the position of the measuring auxiliary probes. The ground resistance is calculated by applying the 61.8% lute using fall-of-potential method.