• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.325-330
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• 2005

Recently an increase of sensor and power trandusers in control equipment system has caused many kinds of noise. These kinds of noise came out the mis-operation equipment and demage program memories of control circuits. In this paper, the noise generation of control equipment system han been measured and analyzed. Additionally, the effective protection equipments to reduce noise like as Noise Cut Transformer, Equipotential Bonding, Power Noise Rejector, Noise Filter has been applied and proposed the measured results.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.361-364
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• 2008

This paper deals with assessment of electrical safety for grounding system of buildings by investigation on the spot at construction site. The investigation was carried out for grounding method, grounding type, shape of grounding electrode, grounding for lightning protection system, continuity of steelwork in reinforced concrete structure and so on. The investigation on the spot was performed by researcher, engineer with over fifteen years of industry experience all over the country. As a result of investigation on the spot to 13 buildings, common grounding method was dominant. A new grounding system based on international standards includes unity grounding system, structure grounding utilizing steel reinforced concrete, equipotential bonding. use of surge protective device.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.1
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• pp.194-202
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• 2017

In this study, we measured and analyzed electrical noise signals present in devices and systems operated in industrial facilities. Based on the analytic findings, we studied the most effective improvement measures for eliminating such noise signals. Leakage current and ground current generate data interferences in communication systems, and therefore we measured leakage current and ground current. We also measured and analyzed electrical noises in power systems to predict noise pathways and interference routes. Furthermore, we proposed the most effective and reliable improvement measures for blocking off various noise signals and safely eliminating them by improving the internal wiring of the facilities and grounding systems. As a final step, we conducted the proposed improvement measures and confirmed that they helped to improve the operations of the device sand systems in service by re-measuring electrical noise signals and comparing them with those measured before the proposed improvement measures were implemented.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.7
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• pp.1290-1294
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• 2016

In this study, we investigate the sources of system malfunctions by measuring and diagnosing various surges and noise signals from grounding systems for electrical and electronic systems and installations in order to ensure the reliability and stability of the system operations. We measured performance or structural problems detected in the grounding systems currently in operation and analyzed the measured data in order to eliminate noise currents and interferences causing the systems to malfunction and be damaged. Based on the analysis results, we proposed improving grounding systems and the wiring arrangements most appropriate for the grounding systems and carried out the installations as per the proposed engineering. We verified that the proposed engineering made the status of system operations improved by measuring the ground noise signals during the system operations and comparing them before and after improvements being carried out.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.195-197
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• 2007

This paper presents experimental results on the safety of persons due to a ground fault in 22.9 kV-Y distribution system In order to evaluate the touch voltages due to internal ground faults in a step down transformer based on the newly prescribed KS C IEC 60364 standard series, the verification tests in a 22.9 kV multi-grounded neutral system were carried out From the experimental results, it was found that there will be significant potential rise jeopardizing LV equipment insulation in case of separate grounding between HV and LV system and the effective measures against hazardous touch voltages due to a IN side ground fault in the common grounding system between HV and LV system are proposed. As a consequence, it was found that the equipotential bonding is an important prerequisite for the effectiveness of the protective measures for the safety of persons in the common ground system between 22.9 kV-Y and low-voltage grounding system.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.343-346
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• 2009

The grounding system of low voltage power systems is TT grounding system in Korea. In order to follow the international standard, TN grounding system is adopted. However, the performance of grounding systems has not been evaluated. This paper deals with the experimental results of protection ability of grounding system when lightning surge invades to the neutral line of low voltage power system. As a result, the TT grounding system is most frail for the lightning surge and it does not protect the electrical devices. On the other hand, the TN grounding system perfectly protects the electrical equipment and prevents the electric shock for human through the equipotential bonding. In case of TN system with supplement grounding, it is very important to lower the supplement grounding resistance to protect the electrical equipment and electric shock for human.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.8
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• pp.113-120
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• 2014

In this paper, designing of an earthing system in accordance with international standards with regard to 22.9kV-y multi-grounded neutral system is discussed and confirmed that the consumer's earthing system can be a part of a global earthing system by interconnecting its earthing system with the neutral conductor of 22.9kV-y multi-grounded system. Further, it is proposed that some modification of the earthing system design flowchart given in the international standards are necessary when considering the equipotential bonding, lightning protection, and telecommunications facilities as well as the basic safety requirements.

• Fire Science and Engineering
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• v.25 no.1
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• pp.50-56
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• 2011

In recently years, occurrences of lightning return strokes have been increased by global worming effect and intensity of lightning impulse voltage and current accompanied by lightning discharges has being strengthening. In Korea, 560 thousand lightning discharges happened in 200S. According to the increasing frequencies of lightning, human deaths and damages to the structure have been increased steadily. Electric fire caused by lightning return strokes due to the breakdown between power line and ground line from the ground potential rise on a process of the lightning impulse current through to the ground. The damages of lightning were occurring at same time in the neighboring areas of the lightning point. In order to protect from the lightning stroke, we made a suggestion to use protection devices and equipotential bonding at the dangerous areas. The analysis results of electric fires caused by lightning would be utilized to investigate and to find accurate fire cause in the fire scenes.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.1
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• pp.141-148
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• 2008

This paper presents experimental results on the safety of persons and protection of low-voltage equipments of the sub-station due to a single-phase ground fault in 22.9 kV-Y distribution system. In order to evaluate the hazard voltages and the stress voltage of the low-voltage(LV) equipment due to faults between high-voltage systems and earth based on the newly prescribed KS C IEC 60364 standard series, the verification tests in a 22.9[kV] neutral multiple grounding system were carried out. From the experimental results, we introduce serious problems causing some discomfort when applying KS C IEC 60364 standard series to the existing domestic distribution system and the effective protective measures against temporary overvoltages due to a ground fault in the common grounding which is combined the 22.9 kV-Y grounding and the customer's installation grounding are proposed. As a consequence, it was found that the equipotential bonding is an important prerequisite for the effectiveness of the protective measures for the safety of persons and LV equipment in the combined 22.9 kV-Y and low-voltage grounding system.