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徐熏徹(Hun-Chul Seo),權五相(O-Sang Kwon),金喆煥(Chul-Hwan Kim),鄭昌守(Chang-Soo Jung),柳然杓(Yeon-Pyo Yoo) 대한전기학회 2006 전기학회논문지A Vol.55 No.7
If the three phases are not balanced, the current in neutral wire is not zero. Then, the induced voltage can be generated in communication line. The KEPCO's rule about unbalanced current for one step type in distribution pole is a twenty percent of phase current. But the unbalanced current for two step type in distribution pole can't decide the rule because there are many different views. This paper presents the calculation and analysis technique of neutral current in distribution poles using equivalent circuit analysis and EMTP simulation.
배전계통에서 분기선로 형태에 따른 뇌서지 전달특성 해석
서훈철(Hun-Chul Seo),한준(Jun Han),김윤곤(Yun-Gon Kim),김철환(Chul-Hwan Kim),최선규(Sun-Kyu Choi),이병성(Byung-Sung Lee),이상봉(Sang-Bong Rhee) 대한전기학회 2013 전기학회논문지 Vol.62 No.10
This paper analyzes the propagation characteristics of lightning surge according to the type of branch line in distribution system. The types of branch line considered are H-type and PI-type. At each type, the length of main feeder is same, while the number and length of branch line are different. The distribution line is modeled and the various lightning locations are simulated by Electromagnetic Transient Program(EMTP). For each lightning, the various measuring points are selected. Based on the simulation results, the propagation characteristics of lightning surge at each measuring point are analyzed. The analyzed results are verified by travelling wave theory.
徐薰徹(Hun-Chul Seo),呂相敏(Sang-Min Yeo),金喆煥(Chul-Hwan Kim),柳永植(Young-Sik Lyu),趙範燮(Burrn-Sup Cho) 대한전기학회 2008 전기학회논문지 Vol.57 No.6
The transformer inrush current can cause a voltage drop by source impedance. This current can impact sensitive loads by the voltage drop. Therefore, it is necessary to take measures to limit this inrush current. This study, described in this paper, analyzes the power quality affected by transformer inrush current using the X power system in Korea. The Electromagnetic Transients Program (EMTP) is used to analyze the transient phenomenon. We discuss a method to model the hysteresis curve of the transformer in EMTP. We carried out various simulations to analyze the power quality during transformer energization. The analysis results of voltage drop by the inrush current occurrence when certain requirements are met are presented.
EMTP-RV를 이용한 GIS에서 VFTO의 상승률 분석
서훈철(Hun-Chul Seo),김철환(Chul-Hwan Kim),정영환(Young-Hwan Chung),류석정(Seok-Jeong Ryu) 대한전기학회 2010 대한전기학회 학술대회 논문집 Vol.2010 No.7
본 논문에서는 EMTP-RV를 이용하여 VFTO의 상승률을 분석하였다. Busbar, 단로기, 차단기 등 GIS의 각 구성요소는 집중정수 및 분포정수 선로로 구성된 전기적 등가회로를 기반으로 모델링 하였으며, 변압기는 제조사에 의하여 주어진 VFT 모델을 이용하였다. 운전가능한 4가지 case를 선정하여 단로기 투입위상각에 따른 시뮬레이션을 수행하여 그 결과를 분석하였다. 또한, 시뮬레이션 결과를 검증하기 위하여 격자도 해석을 수행하였다.
방사상 LVDC 배전계통에서 고장전류의 극성을 이용한 보호 방법
서훈철(Hun-Chul Seo),권기현(Gi-Hyeon Gwon),박건우(Keon-Woo Park) 대한전기학회 2021 전기학회논문지 Vol.70 No.12
The low-voltage DC (LVDC) distribution system is attracting attention due to the increase in DC-based distributed generation and the development of power conversion technology. This technology has various advantages by reducing power consumption through high-efficiency conversion that reduces the number of AC/DC power conversions. In this paper, a new protection method for the stable operation of LVDC distribution system is proposed. The change of fault current according to fault location in LVDC distribution system is analyzed. Based on this, a new protection method using the polarity of the fault current is proposed. The proposed method determines the fault location and transmits a trip signal of circuit breaker (CB) accordingly. For verification of the proposed method, the LVDC distribution system and the proposed method are modeled using Electro Magnetic Transient Program (EMTP). Simulations are performed according to the fault location and fault resistance, and the results are analyzed. The simulation results show that the fault location is accurately determined and the trip signal of CB is transmitted according to the proposed method.