• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.11
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• pp.75-80
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• 2012

In this paper, the operational characteristics due to the introduction of the superconducting fault current limiter(SFCL) with a peak current limiting function were analyzed in the power distribution system. The parallel structure of the superconducting element can operate the peak current limiting function depending on the transient amplitude of fault current. We studied the operating characteristics of the introduction of the SFCL with a peak current limiting function in the power distribution system. Furthermore, we were analyzed between the SFCL with a peak current limiting function and the protection devices in the power distribution system, through the short circuit experiments.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.2
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• pp.113-119
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• 2010

A safe grounding design is used for providing means to carry electric currents into the earth under fault conditions without exceeding any operating limits and for assuring that a person in the vicinity of grounded facilities is not exposed to danger of critical electrical shock. Transformer neutral point grounding is for the purpose of controlling the voltage to earth within tolerable limits under a line-to-ground fault. Transformer frame grounding is for the purpose of minimizing the hazardous potential within safety criteria appearing at the faulted equipment. ills paper deeply investigates the grounding resistance effects of distribution power transformers by analysing the neutral to eatth voltages and touch voltages when the fault occurs.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.391-394
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• 2009

현재 산업사회의 발달과 더불어 신뢰성 높은 양질의 전기에너지와 운전 및 보수의 간편화, 계통운용의 신뢰성의 확보가 요구되고 있다. 또한 $SF_6$을 대체할 친환경적인 절연매체의 개발이 절실히 요구되고 있다. 이에 본 연구는 모의 GIS내 제조공기의 압력 및 캡 변화에 따른 전원별 절연특성을 구명하였다. 또한 배전급 전력설비에 적용을 위하여 제조공기와 $SF_6$의 절연특성을 비교 평가하였다. 제조공기의 절연특성을 구명함으로서 각종 전력응용 설비의 절연설계에 $SF_6$ 대신 친환경적인 모의공기를 사용 가능함을 본 연구에서 구명하였다. 현재 송배전 설비의 절연매체로 사용하고 있는 $SF_6$ 3[atm] 에 상응하는 제조공기의 압력을 인공신경망을 이용하여 추정하여 제조공기를 이용한 친환경적인 절연재 사용으로 지구의 온난화현상 감소에 크게 기여할 것으로 기대된다.

• 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.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.423-427
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• 2009

In the circumstances which a highly reliable operation in electric power facilities of extra high voltage and large capacity is needed, the importance of a preventive diagnostic technology is growing large day and day. The settlement of a preventive diagnostic technology for optimization and efficient management on the electric power facilities like GIS enable the reduce of repair fee, the improvement of safety and the systematic management of electric power facilities. The remaining life prediction of facilities will play a decisive role as a core technology of a preventive diagnostics in the future. And so it is necessary a continuous research and concern for the development of a preventive diagnostic technology hereafter.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.429-434
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• 2009

In this paper it was written about the safety management plan for underground power transmission cable, and it guarantees the reliable electric power supply and facility management to prevent an electric disasters according to that. Recently fires which happens on OF Cable lead to a breakdown of power system and cause a power outage of wide area and serious social problems. So it needs an improvement of inspection ability on OF cable as well as a strict inspection system to prevent that problems in advance and it will bring us the development of electric safety management and the reliable electric power supply.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.9
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• pp.51-58
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• 2015

Intelligent distribution automation system includes operating a switchgear of distribution system remotely when switchgear are not available to operate quickly. This system makes it possible to reduce the interrupt time. It also aims to improve the reliability of customers. Currently, Intelligent distribution automation improves the reliability by replacing manual switchgear, which is installed as sectional switchgear. However the prioritization of the replacement for the switchgear is required for its intellectualization. Many studies have been conducted related with prioritization of switchgear replacement. But it is difficult to interpret and apply to the power distribution system. That is because most of the studies just considers customer numbers for prioritizing the replacement. In this paper presents an algorithm to determine the intelligent swichgear replacement priority considering customer number, load quantity and interruption cost. Further, this algorithm is verified by using system reliability index.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.9
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• pp.33-41
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• 2015

To improve the power quality of distributed generation (DG) systems even in the presence of distorted grid condition, dual current control scheme of a grid-connected inverter is proposed. The proposed current control scheme is achieved by decomposing the inverter state equations into the fundamental and harmonic components. The derived models are employed to design dual current controllers. The conventional PI decoupling current controller is used in the fundamental model to control the main power flow in DG systems. At the same time, the predictive control is applied in the harmonic model to suppress undesired harmonic currents to zero quickly. To decompose the voltage inputs and state variables into the fundamental and harmonic components, the fourth order band pass filter (BPF) is designed in the discrete-time domain for a digital implementation. For experimental verification, 2kVA prototype of a grid-connected inverter has been constructed using digital signal processor (DSP) TMS320F28335. The effectiveness of the proposed strategy is demonstrated through comparative simulation and experimental results.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2001.11a
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• pp.65-72
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• 2001

Power system stabilizer act efficiently to damp the electromechanical oscillations in interconnected power systems. This paper presents an algorithm for the optimal parameter selection of a power system stabilizer in two-area power systems with a series HVDC link. This method is one of the classical techniques by allocating properly pole-zero positions to fit as closely as desired the ideal phase lead between the voltage reference and the generator electrical power and by changing the gain to produce a necessary damping torque over the matched frequency range. Control of HVDC converter and inverter are used a constant current loop. Proper parameters of PI controllers are obtain based on the Root-locus technique in other to have sufficient speed and stability margin to cope with charging reference values and disturbance. The small signal stability arid transient stability studies using the PSS parameters obtained from this method show that a natural oscillation frequency of the studycase system is adequately damped. Also the simulation results using the HVDC converter and inverter parameters obtained from this proposed method show proper current control characteristics. The simulation used in the paper was performed by the Power System Toolbox software program based on MATLAB.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.2
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• pp.29-37
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• 2006

Heavy chemical industries have nonlinear loads including elecrolyzers. AC-DC converters are the most widely used in an elecrolysis in a chemical plant. The electrolysis consists of AC-DC converter groups connected in parallel at the DC side. The converter operations cause harmonic currents and create distortions on the sinusoidal voltage of the AC power system. This paper provides an in depth analysis on harmonics field measurement for the electrolyzer loads and harmonics assessment by the international harmonic standards IEC 61000-3-6 and IEEE 519-1992.