• Proceedings of the KIEE Conference
• /
• 2000.11a
• /
• pp.79-81
• /
• 2000

Measurement used electrical sounding(MacOHM 2115, Japan) for large scale grounding resistance of So-Yang Dam hydroelectric power plant. To applied measurement method is fall of potential method. This result propose to method of efficient administration for grounding system.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2007.11a
• /
• pp.189-193
• /
• 2007

The grounding of an electrical system is one of the essential elements for public safety. Domestic practice of grounding system design has been to get grounding resistance values which are classified by facilities or equipment in the regulations. But the concept of grounding system design of IEC is, as a main factor of safety index, to consider touch voltage and step voltage instead of the resistance value itself. Recently IEC actively develops or revises safety related standards which are essential for the grounding system performance. In this paper, we present the recent trend of the international standards on the safety criteria for Electric Shock Protection.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2004.11a
• /
• pp.241-245
• /
• 2004

The electric safety tends to be more important according to electric facilities's increase and its use in these days. This paper analyzes soil resistivity of two areas in the country using CDEGS(Current Distribution, Electromagnetic Interference, Grounding and Soil Structure, Canada). We designed rod and mesh grounding system and made a comparative study of ground resistance, GPR(Main Electrode Potential Rin), step voltage and touch voltage. Then we could analyz only the safety but also economical efficiency in elocution of grounding. As a result of simulation, ground resistance, GPR(Main Electrode Potential Rise), step voltage and touch voltage became higher in proportion to soil resistivity. Therefore we expect to estimate the propriety of grounding system design through accumulation and analysis of data in consideration of characteristics of soil.

• Journal of the Korean Society of Safety
• /
• v.30 no.2
• /
• pp.9-13
• /
• 2015

This paper describes the analysis of deterioration characteristics for connection factor used in grounding system. The connection method of grounding system is specified in IEC standard. In order to analyze the deterioration characteristics for connection factor, deterioration test was carried out when the connection factor was buried in salt water and underground. The test connection factors were C-type sleeve, clamp, and exothermic welding. As a consequence, most of the connection factor was corroded, and the electrical resistance decreased after deterioration. The analytical results can be used to establish the safety of grounding system.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.50 no.8
• /
• pp.382-386
• /
• 2001

Presently, typical maximum probe spacing of soil resistivity survey(Wenners 4 pin method) is 20 m in case of 154 K substation grounding design of KEPCO. This paper examined the effects of maximum probe spacing of wenner method on the equivalent soil modeling and the accuracy of grounding resistance measurement by comparing the calculated FOP(Fall-of-Potential) curves of various soil models with the measured one at 154kV H substation. The comparison results showed that the inaccurate estimation of deep soil resistivity, which is caused from the short probe spacing of soil resistivity survey, can produce large errors on measurement of grounding resistance. In this paper a quantitative analysis of FOP at H substation has been presented.

• Proceedings of the KIEE Conference
• /
• 1997.11a
• /
• pp.351-353
• /
• 1997

In this paper, we investigate the grounding installation using grounding electrode into the earth in order to protect the power transmission line and transmission system and to improve the reliability of operations. Grounding electrode into the earth that has small grounding resistance is found to be very cost effective compare to other electrode systems by the ease of installation and making the earth damage small.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2008.05a
• /
• pp.313-316
• /
• 2008

This paper presents the error factors of Fall-of-potential test method used in measurements of the grounding-system impedance. This test methods inherently can introduce two possible errors in the measurements of grounding-system impedance: (1) ground mutual resistance due to current flow through ground from the ground electrode to the current probe, (2) ac mutual coupling between the current test lead and the potential test lead. The errors of ground mutual resistances and ac mutual coupling are expressed by the equation in calculating grounding impedance. These equations were calculated by Matlab that is commercial tool using mathematical calculation. The results of calculation were applied to correct grounding impedance.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.24 no.6
• /
• pp.60-66
• /
• 2010

Mesh grounding electrodes in Korea and abroad are designed as lattice-shaped equidistance grounding grids. In case of a lattice-shaped grounding Grid, however, there is a problem of higher touch voltage at the corner of the grid relative to the center. To overcome this problem, we used oblique-shaped equidistance grounding grid to reduce the area of the corner where mesh voltage occurs. As a result the mesh voltage was reduced. Therefore, this paper suggests the use of oblique-shaped grounding grid instead of the existing lattice-shaped ones. It applied the same grounding design dimensions for both lattice-shaped and oblique-shaped grounding grids, compared and analyzed mesh voltage, GPR, ground resistance, total length of grounding conductor, verified that oblique-shaped grounding grid is superior to the lattice-shaped.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.63 no.3
• /
• pp.331-337
• /
• 2014

The Korean distribution system consists of overhead ground wire (OHGW), phase conductors and neutral wire. Especially, OHGW is installed over the phase conductors to protect distribution system from the lightning surge. The flashover rate and the magnitude of lightning overvoltage on distribution system can be affected by grounding condition of OHGW such as grounding resistance and grounding interval. In this paper, we conduct an analysis of lightning overvoltage and flashover rate according to the grounding condition of OHGW. The distribution system and lightning surge are modeled by using ElectroMagnetic Transient Program (EMTP). Also, the Monte Carlo method is applied to consider random characteristics of lightning, and the flashover rate is calculated based on IEEE std. 1410. The simulations are performed by changing the grounding resistance and interval of OHGW and the simulation results are analyzed.

• Journal of the Korean Society of Safety
• /
• v.31 no.1
• /
• pp.48-53
• /
• 2016

This paper deals with analysis of complex grounding system using electromagnetic simulation method. Electrical devices could be damaged by transient voltage such as a lightning surge. Therefore the measures to protect the equipments from transient, such as a lightning are required. The ground system is important in this respect. The representative parameter of grounding system performance is earth ground resistance. Precise prediction of earth resistance is required, because it is difficult to modify and change after the completion of the grounding system construction. Numerical modeling is often used in numerical analysis to identify the electrical characteristics of the grounding system. However complex systems are difficult to predict grounding characteristics by numerical analysis. If the total electric field of the earth in general is similar to the antenna model, in that the incident electric field and expressed as a sum of the scattering field. In this study, the electromagnetic field simulation tool "ANSYS HFSS" module containing the antenna model was used to analyze performance of ground system. Both the simple and complex grounding system were analyzed by simulation tool and experimental method. As a result simulation method is effective to predict performance of a complex ground system.