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노철호(Chul-Ho Noh),김충모(Chung-Mo Kim),김두웅(Doo-Ung Kim),권기현(Gi-Hyeon Gwon),오윤식(Yun-Sik Oh),한준(Jun Han),김철환(Chul-Hwan Kim) 한국조명·전기설비학회 2015 조명·전기설비학회논문지 Vol.29 No.4
Recently, DC-based power system is being paid attention as the solution for energy efficiency. As the example, HVDC (High Voltage DC) transmission system is utilized in the real power system. On the other hand, researches on LVDC (Low Voltage DC) distribution system, which are including digital loads, are not enough. In this paper, reliability in LVDC distribution system is analyzed according to the specific characteristics such as the arrangement of DC/DC converters and the number of poles. Furthermore, power quality is also taken account of since LVDC distribution system includes multiple sensitive loads and electric power converters. In order to achieve this, LVDC distribution systems are modeled using ElectroMagnetic Transient Program (EMTP) and both the minimal cut-set method and Customer Interruption Cost (CIC) are used in the reliability analysis.
노철호(Chul-Ho Noh),김두웅(Doo-Ung Kim),권기현(Gi-Hyeon Gwon),오윤식(Yun-Sik Oh),한준(Jun Han),김철환(Chul-Hwan Kim) 한국조명·전기설비학회 2015 조명·전기설비학회논문지 Vol.29 No.11
AC-based power systems, having the advantages that voltage transformation and long distance transmission are easy, have been constructed since the last 19th century. However, DC-based power system is paid attention these days because of the development of power electronic devices as well as the increase of digital loads and distributed generation. For instance, the transmission systems using High Voltage DC (HVDC) are commercially operated in the world and the researches on distribution system using Low Voltage DC (LVDC) are gradually increased. This paper analyzes voltage sag, resulted from faults, in LVDC distribution system according to the number of poles. Modeling and simulation with various conditions are conducted by using ElectroMagnetic Transients Program (EMTP). Moreover, some countermeasures to reduce voltage sag in LVDC distribution system are suggested briefly.
교류 측 보호기기 동작에 기인한 저압직류 배전계통의 과도특성에 관한 연구
노철호(Chul-Ho Noh),권기현(Gi-Hyeon Gwon),김철환(Chul-Hwan Kim) 한국조명·전기설비학회 2017 조명·전기설비학회논문지 Vol.31 No.4
In recent, DC-based power system is being paid attention as the solution for improving the energy efficiency as distributed generations based on renewable energy and digital devices increase. The interest is gradually extended to Low Voltage DC (LVDC) distribution system. To establish the standards for LVDC distribution system, the studies on various aspects based on the comparative analysis between AC system and DC system have conducted. Protection schemes for LVDC distribution system are also included, but most researches have focused on transient characteristics under DC faults so far. This paper, therefore, analyzes the transient characteristics in LVDC distribution system resulted from the operation of protective device by AC fault. Furthermore, it is proposed the considerations to construct the reliable protection schemes. For this purpose, theoretical analysis with the equivalent circuits of LVDC distribution system is performed, and then the analysis results are verified through simulations with ElectroMagnetic Transients Program.