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민명환(Myung-Hwan Min),고유란(Yu-Ran Go),안태풍(Tae-Pung An),이태훈(Tae-Hoon Lee),이병곤(Byeong-Gon Lee) 대한전기학회 2019 전기학회논문지 Vol.68 No.12
This paper carries out the power analysis in case of regenerative power generation in the AC power supply system, which is using the scott transformer. In particular, the three phase power characteristics of the primary side are analyzed numerically according to the single phase power characteristics of the secondary side of the transformer. More specifically, the power characteristics of the three-phase side are presented by classifying the cases according to the conditions of accelerated and regenerative operation of the secondary side of the transformer. In addition, the power characteristics presented in this paper are verified by comparing the values analyzed numerically with those measured at the substation.
국내 기준과 IEC 표준을 적용한 교류철도 급전계통에서의 불평형률 분석
민명환(Myung-Hwan Min),고유란(Yu-Ran Go),안태풍(Tae-Pung An),이태훈(Tae-Hoon Lee),이병곤(Byeong-Gon Lee) 대한전기학회 2019 전기학회논문지 Vol.68 No.12
AC railway system which has a large single-phase AC load causes voltage unbalance. The voltage unbalance can effect to decrease efficiency, life time of installed devices in three-phase supply system. In this paper, the definition of voltage unbalance factor and the limiting value are compared and investigated. Among them, the methods of analysis and evaluation presented by IEC (IEC 61000-3-13) standards are introduced. In addition, the voltage unbalance factor was calculated using the actual measured voltage at the AC railway substations by the methods given in the national and IEC standards. In conclusion, the characteristics of the voltage unbalanced rate in the AC railway system are to be identified.
민명환(Myung-Hwan Min),정호성(Hosung Jung),박영(Young Park),창상훈(Sang-Hoon Chang),신명철(Myong-Chul Shin) 대한전기학회 2012 전기학회논문지 Vol.61 No.3
Nowadays, in metropolitan railroad, DC feeding system is being generally applied. In order to reduce damage of electro-chemical corrosion caused by stray current and leakage current, in DC feeding system, rail is used as negative-polarity return conductor for traction load current. However, it has problem of rail potential increase and there are no adequate measures to prevent it in domestic. The rise of rail potential leads to damage for human and equipments. To solve the problems, this paper presents fundamental theory and related standards about rail potential increase. And then, we analyzed field testing data and simulated a variety of operations by using PSCAD/EMTDC as an analysis program of power system. In addition, this paper suggests rail potential limit device and addresses how to the device. To verify the effect, simulation of DC feeding system before and after the application of the device is carried out in various cases.
직류급전계통에서의 레일전위 상승 분석 및 억제 방안 연구
민명환(Myung-Hwan Min),정호성(Hosung Jung),박영(Young Park),김형철(Hyengchul Kim),신명철(Myong-Chul Shin) 대한전기학회 2011 전기학회논문지 Vol.60 No.3
Nowadays, in metropolitan railroad, DC feeding system is being generally applied. In order to reduce damages of electro-chemical corrosion caused by stray current and leakage current, in DC feeding system, rail is used as negative-polarity return conductor for traction load current. However, it has problem of rail potential increase and there are no adequate measures to prevent it in domestic. In this paper, we presented fundamental theory and related standards about rail potential increase. And then, we analyzed field testing data and simulated a variety of operations by using PSCAD/EMTDC as an analysis program of power system. In addition, voltage control device is suggested to prevent accidents caused by rail potential increase.
교류철도계통의 계측신호 분석을 통한 전압불평형율 및 전압왜형율 처리에 관한 연구
민명환(Myung-Hwan Min),홍재영(Jae-Young Hong),고유란(Yu-Ran Go),안태풍(Tea-Pung An),이태훈(Tea-Hoon Lee) 대한전기학회 2021 전기학회논문지 Vol.70 No.12
In this paper, the existing analysis method for the total harmonic distortion (THD) and the voltage unbalance among power quality is presented. The existing method calculates based on the measured voltage value, but it is difficult to derive only the power quality value of railway operation since the voltage is affected by the commonly connected system. This study proposes a method of calculating the measured current value, power value, and system short-circuit capacity value. In order to verify the validity of the proposed method, the basic method and the proposed method were compared and analyzed based on the actual measured signals in the AC railway substation.