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5kV급 MV-LVDC 배전망의 보호협조 연구를 위한 실계통 모델링
정판검,최성균,정인성 조선대학교 공학기술연구원 2023 공학기술논문지 Vol.16 No.3
Recently, the need for MVDC distribution systems has been rapidly increasing all over the world due to the introduction of renewable energy sources, the increase of DC loads, and consumers' high-quality and high-reliability power demands. Empirical research is being conducted to apply to the MVDC distribution network using existing AC devices and lines. However, in case of using existing AC devices, expensive facilities such as converters and tracks may not be stably protected if the accident happens. For that reason, analysis of the accident characteristics for the stable operation of the MVDC distribution network is required. Therefore, in this paper, using PSCAD/EMTDC, a power system analysis program, a protection cooperation system was modeled targeting a 5kV class MV-LVDC distribution network which was built in Naju, Jeollanam-do and is under trial operation. In the future, we plan to conduct research to examine the validity of protection cooperation through accident analysis of 5kV class DC power distribution networks based on the relevant modeling.
열처리공정에 따른 층상 ReSe2 디바이스의 접촉 저항 개선 연구
정판검,이동진,고필주 조선대학교 공학기술연구원 2017 공학기술논문지 Vol.10 No.1
The two-dimensional(2D) materials, including graphene, h-BN, layered transition metal–chalcogenides (TMC) and layered transition metal-dichalcogenides(TMDCs) are the next generation of the opto-electronic devices. In this paper, we report on the opto-electronic properties of back-gated field effect transistor(FET) based on ∼ 200 layered ReSe2 at before and after annealing. After the annealing, the transition from schottky to ohmic contact in the Ti electrodes and ReSe2 was observed, and the external quantum efficiency (EQE) of the ReSe2 device was by increased 10% due to the improvement of the contact resistance between the electrodes and ReSe2. We obtained an EQE of 18.8% and 8.2% using 532 nm laser excitation, and ReSe2 device is a good candidate for 2D material based ultra-thin opto-electronic device applications.
열처리공정에 따른 층상 ReSe<sub>2</sub> 디바이스의 접촉 저항 개선 연구
정판검 ( Pan Gum Jung ),이동진 ( Dong Jin Lee ),고필주 ( Pil Ju Ko ) 조선대학교 공학기술연구원 2017 공학기술논문지 Vol.10 No.1
The two-dimensional(2D) materials, including graphene, h-BN, layered transition metal-chalcogenides (TMC) and layered transition metal-dichalcogenides(TMDCs) are the next generation of the opto-electronic devices. In this paper, we report on the opto-electronic properties of back-gated field effect transistor(FET) based on ∼ 200 layered ReSe<sub>2</sub> at before and after annealing. After the annealing, the transition from schottky to ohmic contact in the Ti electrodes and ReSe<sub>2</sub> was observed, and the external quantum efficiency (EQE) of the ReSe<sub>2</sub> device was by increased 10% due to the improvement of the contact resistance between the electrodes and ReSe<sub>2</sub>. We obtained an EQE of 18.8% and 8.2% using 532 nm laser excitation, and ReSe<sub>2</sub> device is a good candidate for 2D material based ultra-thin opto-electronic device applications.
BLT 박막의 CMP 공정시 압력에 따른 Surface Morphology 및 Defects 특성
정판검(Pan-Geum Jung),이우선(Woo-Sun Lee) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.10
PZT thin films, which are the representative ferroelectric materials in ferroelectric random access memory (FRAM), have some serious problem such as the imprint, retention and fatigue which ferroelectric properties are degraded by repetitive polarization. BLT thin film capacitors were fabricated by plasma etching, however, the plasma etching of BLT thin film was known to be very difficult. In our previous study, the ferroelectric materials such as PZT and BLT were patterned by chemical mechanical polishing (CMP) using damascene process to top electrode/ferroelectric material/bottom electrode. It is also possible to pattern the BLT thin film capacitors by CMP, however, the CMP damage was not considered in the experiments. The properties of BLT thin films were changed by the change of polishing pressure although the removal rate was directly proportional to the polishing pressure in CMP process.
±35kV MVDC 스테이션의 실제 지락사고 및 시뮬레이션 비교분석에 관한 연구
오정식,정판검,정인성 조선대학교 공학기술연구원 2024 공학기술논문지 Vol.16 No.4
The MVDC distribution is a promising solution for future decentralized electrical networks with a large amount of distributed renewable-energy generation and storage systems. Recently, demonstration projects on an MVDC distribution network have been actively carried out to increase the capacity of an existing AC distribution system. However, since there are no specific protection guidelines for an MVDC station, which is a key facility for power conversion, operation methods of protection devices are required. In this paper, in order to analyze the accident characteristics of the distribution system of the MVDC distribution network, we compared and analyzed the ground fault accidents that occurred in the actual MVDC system and the simulation results. A comparative analysis was performed based on simulation results when a ground fault occurred in the DC link of a 30MW±35kV rated MVDC system and measured values when an actual ground fault occurred.