• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.263-266
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• 2003

The gate leakage current is first calculated using the experimental method between gate and drain by opening source electrode. Next, the gate to drain current has been obtained with a ground source. The difference of two current has been tested and provide that the existence of another source to Schotuy barrier height against the image force lowering effect.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.233-236
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• 2000

A portable equipment that measures a current and voltage waveform of power transmission lines is pro-posed. In the equipment, the current and voltage, respectively, are detected by a loop coil and a capacitor clamped around the power lines. The detected data is transmitted by an FM wave to the receiver on the ground station. Since the receiver is isolated from the power lines, we do not require high potential insulators for the measurement of current and voltage. The proposed equipment is therefore, small-sized, light, and low in the cost of production. Experimental results presented here show that the equipment can monitor the current flowing in single wire over a ground plane and the potential of the wire.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.2
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• pp.363-369
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• 2017

This paper presents the experimental results related to soil ionization and electrical breakdown in a concentric hemispherical electrode system under lightning impulse voltages. Dynamic voltage-current and impedance-time characteristics of soil ionization were measured and analyzed. Also the electrical breakdowns of the soil gap were investigated. The time-lag to the peak current corresponds to the soil ionization propagation. The time of ionization propagation in wet sand is found to decrease with increasing the impulse currents. A drastic decrease in ground resistance was observed during the impulse current spreading in sand. The electrical breakdown appears at the wave tail of impulse voltage and results in a wide scatter in V-t curves. The voltage-current curves have a fan-like shape attributed to ionization processes which result in increasing current and decreasing voltage.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.454-457
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• 2007

This study suggests a modeling of grid-connected wind turbine generation system that has induction generator, and aims to perform simulations for outputs by the variation of actual wind speed and for fault current of wind generation system by the transformer winding connection. This study is implemented by MARTLB & SIMULINK. The simulation shall be performed by assuming single line to ground fault generated in the system Generator power, rotor speed, terminal voltage, system voltage, and fault current shall be observed following the performance of simulation. The fault current change will be dealt through the simulation results for fault current of wind generation system following the grid-connected transformer winding connection and the simulation result by the transformer neutral ground method.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.6
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• pp.562-567
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• 2020

In this paper, this is a study on the correction of protection relays to monitor temporary power facilities for storage tanks especially transformers to block and protect faults such as insulation breakdown. When an abnormality such as a short circuit or a ground fault occurs in the power system, it is important to detect this quickly cut off the device and equipment in which the fault occurred and separate it from the power system to correct the protection relay so that it does not interfere with power supply. In addition the fault current calculation that accurately applies the fault type and the cause of the fault for protection cooperation will be the most important factor in the correction of the protection relay. For protection coordination a study was conducted on the method of coordination for protection of power facility protection for storage tanks such as over current relay, ground over current relay, under voltage relay, and ground over voltage relay applied to temporary.

• International Journal of Safety
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• v.7 no.2
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• pp.1-6
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• 2008

In this paper, the effects of the position and the angle of the potential probes on the measurements of the ground resistance using the fall-of-potential method are described and the testing techniques for minimizing 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 and angle of auxiliary probes. In order to analyze the relative error in the measured value of the ground resistance due to the position of the potential probe, the ground resistance was measured for the case in which the distance of the current probe was fixed at 50[m] and the distance of the potential probe was located from 10[m] to 50[m]. Also, the potential probe was located in turn at $30[^{\circ}]$, $45[^{\circ}]$, $60[^{\circ}]$, $90[^{\circ}]$, and $180[^{\circ}]$. As a consequence, relative error decreased with increasing distance of the potential probe and decreasing angle between the current probe and potential probe. The results could help to determine the position of the potential probe during the ground resistance measurement.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.2
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• pp.96-102
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• 2009

In this paper, the effects of the position and the angle of the potential probes on the measurements of the ground resistance with the 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 and angle of auxiliary probes. In order to analyze the relative error for measuring value of ground resistance due to the position of the potential probe, ground resistance were measured in case that the distance of current probe was fixed at 50[m] and the distance of potential probe was located from l0[m] to 50[m]. Also, the potential probe was located at 30[$^{\circ}$], 45[$^{\circ}$], 60[$^{\circ}$], 90[$^{\circ}$] and 180[$^{\circ}$]. As a consequence, relative error decreased with increasing the distance of potential probe and decreasing the angle between current probe and potential probe. The results could be help to determine the position of potential probe when the ground resistance was measured at grounding system.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.324-327
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• 2009

This paper presents the transient impedance in a discharge region when high voltage lightning impulse is applied to small-sized ground electrodes in frozen soil. For a realistic analysis of ionization characteristics near the ground electrode in the soil, ground rod installed outdoors and high voltage impulse voltage generator were used. From the analysis of response voltage and current flowing ground electrode to earth, it was verified that the ionization near the ground electrode contributes to reduction of ground impedance and limits the ground potential rise effectively under high impulse voltage.

• 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.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.385-386
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• 2023

In this application study, field pilot tests were performed to evaluate the validity of a proposed formula between the exerted electrical energy and SPT N-value based on the result of the basic study. Measurement sensors and recording system were developed to obtain exerted motor current and drilling depth in a field. By using the correlation formula proposed in the basic study, the measured motor current and boring speed were applied to predict SPT N-value and the predicted N-values were compared to SPT N-value of site exploration. From the comparisons it is verified that the exerted electrical energy to bore ground might be used to predict SPT N-value and pile tip location.