• 조명전기설비학회논문지
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• 제26권3호
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• pp.73-79
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• 2012

A counterpoise is commonly employed in grounding systems installing near the ground surface of low resistivity soils and radial-type counterpoises are used in the limited space. Recently some studies on the evaluation of ground impedance of paralleling ground electrodes have carried out, but the data for providing the frequency-dependent ground impedances considering potential interferences are not yet sufficient. In order to provide the information about the design of grounding systems for surge protection, the simulations of the frequency-dependent ground impedance of various shaped counterpoises are carried out by using the distributed parameter circuit model including the effect of potential interferences. This paper presents the theoretical simulations and actual experiments of the frequency-dependent ground impedance of paralleling and 3 or 4-arms star counterpoises. The accuracy of the simulation methodology is examined by the comparison with the measured results, and the results show a good agreement between the simulation and the experiment.

• 전기학회논문지
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• 제61권4호
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• pp.503-508
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• 2012

Among the high distribution voltage consumers, high-capacity consumers are often applying the grounding resistance method in order to overcome demerits such as erroneous operation of the ground reply or potential increase in the battery at the accident of the isolated neutral system. In this paper, to prevent damage to CLR and GPT in the delay to block the breakdown in the resistance grounded neutral system, this study aims to provide a proper suggestion for continuous rating capacity of GPT to check the appropriateness of CLR size and reduce GPT burden. Thereupon, this study comparatively analyzes CLR current applied in general GPT and the current gained when CLR demanded in the system is used and analyzes the simulated system through simulation using PSCAD/EMTDC in order to suggest GPT's proper continuous rating capacity.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 C
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• pp.1179-1181
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• 1998

This paper describes the induced voltage of sheath on 154kV transmission power cable in multi fault states. Simulation was carried out to obtain the induced voltage of sheath according to change of, fault angle and grounding resistance using EMTP. Modeling of cable system is also established in EMTP to analyze. The simulation results can be useful reference to design cable system in power system.

• 조명전기설비학회논문지
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• 제20권5호
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• pp.92-98
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• 2006

본 논문은 봉상접지전극 주변에서 접지전극간 전위간섭에 대해 다루었다. 접지전극 상호간의 전위간섭을 저감하는 기법을 제안하기 위해서 실규모 접지전각에서 발생될 수 있는 대지전위와 전위간섭을 이론적 해석과 축소모델 실험을 이용하여 실험적으로 분석하였다. 반구형 수조모의접지 실험장치로 접지전극 상호간 이격거리에 따른 전위 상승과 전위간섭계수를 측정하고, CDEGS 소프트웨어를 이용하여 이들 현상을 해석하였다. 그 결과 전위상승과 전위간섭계수는 접지전극의 이격거리에 강하게 의존하였으며, 실측결과는 이론적 계산결과와 잘 일치는 결과를 얻었다.

• 조명전기설비학회논문지
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• 제27권2호
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• pp.54-61
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• 2013

This paper presents transient response behavior and frequency-dependent ground impedance of a single carbon ground electrode. The ground impedance of the carbon ground electrode was measured as a function of frequency of injected currents and simulated by using the distributed parameter circuit model with due regard to the frequency-dependent soil parameters, and the transient response behavior of the carbon ground electrode against impulse currents were investigated. As a consequence, the frequency-dependent ground impedance of the carbon ground electrode showed the capacitive behavior, that is, the ground impedance decreases with increasing the frequency of injected currents and lowers at the fast front time of impulse current. It was found that the carbon ground electrode is effective in grounding system for lightning protection. The ground impedance simulated with due regard to the frequency-dependent soil parameters was in good agreement with the measured data. The adequacy of the simulation technique and the distributed parameter circuit model for the carbon ground electrode was verified. It is expected that the simulation methodology, which analyzes the frequency-dependent ground impedance of the carbon ground electrode proposed in this work, can be used in the design of a grounding system for protection against lightning.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.446-448
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• 2001

Railway electrification results in Electromagnetic Interference, which affects a life and a equipment. Therefore, a plan against EMI must be considered. This study presents accurate simulation to examine a reason rail potential rise and how to design ground connection and draw up a plan of an optimal buried grounding system according to section.

• 한국항해항만학회지
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• 제38권6호
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• pp.689-694
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• 2014

The Korean government has introduced and enforced maritime traffic safety assessment to secure traffic safety since 2010. The maritime traffic safety assessment is needed by law to design a new port or modify an existing one. According to Korea Maritime Safety Act, in the assessment the propriety of marine traffic system consists of the safety of channel transit and berthing/unberthing maneuver, safety of mooring, and safety of marine traffic flow. The safety of channel transit and berthing/unberthing maneuver can be evaluated only by ship-handling simulation. The ship-handling simulation is carried out by sea pilots working with the port concerned. The vessel's proximity measure is an important factor to evaluate traffic safety. The proximity measure is composed of vessel's closest distance to channel boundary and probability of grounding/collision. What is more, the probability of grounding becomes important. According to central limit theorem, a sample has a normal distribution on condition that its size is more than 30. However, more than 30 simulation runs bring about the increase of assessment period and difficulty of employing sea pilots. Therefore this paper is to find out minimum sample size for evaluating vessel's proximity. First sample sets of size of 3, 5, 7, 9 etc. are selected randomly on the basis of normal distribution. And then KS test for goodness of fit and t-test for confidence interval are applied to each sample set. Finally this paper decides the minimum sample size. As a result this paper suggests the minimum sample size of 5, that is, the simulation of more than five times.

• 조명전기설비학회논문지
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• 제22권8호
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• pp.18-25
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• 2008

본 논문은 HATLAB/Simulink에서 계통연계 풍력발전시스템의 특성해석을 위한 모델링을 제안하여 시뮬레이션을 수행한다. 이를 위해 풍속의 변화에 따른 발전기의 출력제어를 위해 피치제어를 수행하며, 연계변압기의 결선방법에 따른 고장전류의 변화를 살펴봄으로 하여 연계변압기의 결선방법과 고장전류와의 상관관계를 제시하였다. 아울러 풍력발전시스템의 연계변압기 중성점접지방식이 고장전류에 미치는 영향을 살펴본다. 계통에서의 1선 지락고장에 대해 연계변압기의 4가지 결선방식의 차이에 따른 고장전류, 전압 및 발전기의 특성 변화를 확인할 수 있었으며 중성점 접지방식의 차이에 따른 고장전류의 변화를 확인하였다. 사례연구를 통하여 제안한 Simulink에서의 시뮬레이션 모델의 효용성을 입증하였다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2002년도 학술대회논문집
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• pp.343-347
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• 2002

This paper analyzed the effect of breakdown electric current and it establishes a countermeasure that objective of the place where it put when with protection method which is applied from the existing electric railroad power supply system and where the protection method which is applied in the newly electrified system. Will reach and in order to attain simulation it did a actual power supply system and it analyzed that result.

• 조명전기설비학회논문지
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• 제22권4호
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• pp.68-77
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• 2008

국내 접지설계시 가장 널리 사용되는 것은 IEEE Std. 80 위험전압 계산식이나 국내 접지설계 환경의 적정성 여부는 검토되지 않고 있다. 따라서, 본 논문에서는 IEEE Std. 80 접촉전압 계산식의 적용한계를 검토하고 그 문제점을 극복하기 위해 IEEE Std. 80 접촉전압값과 컴퓨터 모의실험값을 비교하여 접촉전압 계산식의 보정계수 $K_a$를 유도하였다. 또한, 유도된 모델 중 Logistic 모델 형식의 보정계수를 적용할 경우 최대 오차율이 10[%]미만인 것을 검증함으로써 고가의 프로그램을 사용하지 않고도 안전하고 경제적인 접지설계를 할 수 있는 방법을 제시하였다.