• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.54 no.5
• /
• pp.224-226
• /
• 2005

In this paper, the secular changes of buried grounding electrodes was investigated; the electrodes are such facilities as grounding grid, grounding connector, grounding terminal and grounding rod etc.. The corrosiveness of removed substation grounding electrodes after commercial operation more than 50 years was measured and its conductivity deterioration trend was analyzed. The measuring results using three experimental methods were compared, finally the consideration for safe and economic grounding design were shown. As the result, it shows the maintenance necessity of grounding systems.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.6
• /
• pp.1103-1108
• /
• 2010

A grounding electrode has the transient grounding impedance characteristics against lightning surges. So the performance of grounding electrodes should be evaluated as a grounding impedance as well as the ground resistance. The frequency-dependent grounding impedance is varied with the shape and size of grounding electrode and is divided into both inductive and capacitive behaviors. This paper presents a theoretical analysis for the grounding impedance determined by the size of grounding electrode using the distributed parameter circuit model. EMTP and Matlab programs were used in calculating the frequency-dependent grounding impedances of vertical grounding electrodes. It was found that the frequency-dependent grounding characteristics of vertical grounding electrodes are characterized by the distributed parameters which are changed in the dimension of grounding electrodes.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.20 no.4
• /
• pp.29-36
• /
• 2006

This paper deals with the potential interferences between grounding electrodes in various grounding electrodes. The ground potential rise and potential interference coefficients were measured by using and electrolytic tank and calculated by CDEGS program as functions of the configuration and size of grounding electrodes and the distance between grounding electrodes. The ground potential rise and potential interference coefficient strongly depend on the distance between grounding electrodes, the shape and size of grounding electrodes. The potential rise interferences between grounding grid and grounding grid is lower than those between grounding grid and ground rod.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2007.11a
• /
• pp.333-336
• /
• 2007

This paper deals with assessment of potential interference between grounding electrodes using ETM(Electrolytic Tank Modeling) method. When a test current flowed through grounding electrode, potential rise was measured and analyzed using an electrolytic tank in real time. In order to analyze the potential interference between grounding electrodes, ETM method was studies. Potential interference between isolated grounding electrodes was evaluated as functions of the separation distance between grounding electrodes and the configuration of grounding electrode to be induced. It was found that the separation distance between grounding electrodes in reducing the potential interference was a major factor.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.22 no.3
• /
• pp.27-33
• /
• 2008

This paper deals with the assessment of potential interference between individual grounding electrodes using an Electrolytic Tank Modeling method. When a test current was passed through a grounding electrode, potential rise was measured and analyzed using an electrolytic tank in real time. In order to analyze the potential interference between grounding electrodes, a reduced scale modeling method was studied. Potential interference between isolated grounding electrodes was evaluated as a function of the separation distance between grounding electrodes and the configuration of grounding electrode to be induced. It was found that the separation distance between grounding electrodes was a major factor in reducing the potential interference.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.5
• /
• pp.85-91
• /
• 2011

A grounding system is generally composed of several vertical, horizontal electrodes or grids. Excessive ground potential rises due to adjacent grounding electrodes can cause failures or misoperation of electronic devices and control systems. It is therefore necessary for computer-related and information-oriented equipment to be placed at a sufficient distance from the areas influenced by grounding electrodes. In this paper, in order to propose a method for evaluating the ground potential rise and interference in the vicinity of vertical grounding electrodes, the experimental and theoretical results on the potential interference between vertical grounding electrodes and its frequency dependence were described. The ground potential rise is sharply decreased with increasing the distance between grounding electrodes. In case that the separation of vertical grounding electrodes is less than 1.5[m], the potential interference coefficient was greater than 0.1 and linearly increased with the frequency of the test current within the frequency of 1[MHz].

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.21 no.4
• /
• pp.73-79
• /
• 2007

In order to analyze the potential rise of grounding systems installed in buildings, a hemispherical grounding simulation system was studied. Potential rise was measured and analyzed regarding the shape and distance of the grounding electrodes by using this system. The system was composed of a hemispherical water tank, AC power supply, a movable potentiometer, and test grounding electrodes. The potential rise was measured in real time by the horizontal moving probe of be potentiometer. The test grounding electrodes were fabricated through reducing the grounding electrode installed in real buildings such as the ground rod, grounding grid and so on. The potential rise was displayed in a two-dimensional profile and was analyzed regarding the shapes of the ground electrodes. The potential rise of the grounding grid combined with a ground rod was the lowest of every grounding electrode tested. The proposed results can be applicable to evaluating ground potential rise in grounding systems, and the analytical data can be used to stabilize the electrical installations and prevent electrical disasters.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.5
• /
• pp.54-60
• /
• 2011

This paper presents characteristics of frequency-dependent grounding impedance and transient grounding impedance for the carbon compound grounding electrode used in the installation of computerized electronic equipment and lightning protection system. The frequency-dependent grounding impedances were measured by applying sinusoidal currents in the frequency range from 100 [Hz] to 10[MHz], and the transient grounding impedances were examined by subjecting the impulse current with the front-time between 1~80[${\mu}s$]. As a result, the ground resistance of the carbon compound grounding electrode is less than that of another type grounding electrodes. The transient grounding impedance is relatively low and the conventional grounding impedance is rather lower than the ground resistance. The frequency-dependent grounding impedance of the carbon compound grounding electrode is capacitive and the grounding impedance is decreased with increasing the frequency of injected currents. Therefore in the case that the carbon compound grounding electrode is jointly used with large-scaled grounding electrodes, it is possible to reduce the high frequency grounding impedance of the integrated grounding electrode system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.26 no.9
• /
• pp.57-63
• /
• 2012

The basic purpose of grounding is for human safety and normal operation of system related to electrical shock hazard by faults of electrical equipments. A grounding electrode is defined as a conducting element that connects electrical systems and/or equipment to the earth. The lowest possible resistance connection to the earth is sought from the grounding electrode. The grounding electrode is the foundation of the electrical safety system. The resistance to ground of vertical electrodes buried in the two deference soil structures has been analyzed for a length of electrodes and soil parameters. The equation of ground resistance of vertical electrodes are Tagg's equation for uniform soil models, and modified equation of Dwight equation for two-layer soil model. In this paper, compared with results of two equations are calculated values of vertical electrode in uniform and two-layer soil models.

• KIEE International Transactions on Electrophysics and Applications
• /
• v.4C no.5
• /
• pp.207-214
• /
• 2004

This paper presents the characteristics of transient and effective impulse impedances for deeply driven grounding electrodes used in soil with high resistivity or in downtown areas. The laboratory test associated with the time domain performance of grounding piles subjected to a lightning stroke current has been carried out using an actual-sized model grounding system. The ground impedances of the deeply driven ground rods and grounding pile under impulse currents showed inductive characteristics, and the effective impulse ground impedance owing to the inductive component is higher than the power frequency ground impedance. Both power frequency ground impedance and effective impulse ground impedance decrease upon increasing the length of the model grounding electrodes. Furthermore, the effective impulse ground impedances of the deeply driven grounding electrodes are significantly amplified in impulse currents with a rapid rise time. The reduction of the power frequency ground impedance is decisive to improve the impulse impedance characteristics of grounding systems.