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Operational Characteristics of the FCL Using the Mechanical Contact in the Power System
Byung ?Ik Jung(정병익),Hyo-Sang Choi(최효상) 대한전기학회 2016 전기학회논문지 Vol.65 No.5
These days, SFCLs are being developed in order to limit fault current. However, the superconducting elements that limit the fault current have such problems as capacity increase and require auxiliary devices including cooling device. If devices that comprise the current power network can withstand fault current for at least one cycle, it is possible to limit the fault current with current limiting elements by bypassing it on the fault line. In this study, the fault current limiter was configured with current transformer, vacuum interrupter, and current limiting element. Through the experience, it was confirmed that the fault current was limited within one cycle. The superconducting element, as a current limiting element, limited the fault current by 80 % within one cycle from fault occurrence, and the passive element limited it more than 95 %. Also, through the comparison between resistance curve and power consumption curve, it was confirmed that the current limiting element using a passive element was more stable than the superconducting element that required capacity increase and other auxiliary devices. It was considered that the FCL proposed in this study could limit fault current stably within one cycle from fault occurrence by using the existing power technologies such as fault current detection and solenoid valve operating circuit.
Byung ?Ik Jung(정병익),Hyo-Sang Choi(최효상) 대한전기학회 2016 전기학회논문지 Vol.65 No.5
This paper proposed the structure that applied superconductors to the neutral line of a transformer and applied the normal conductors to the third line. The superconductor applied to the neutral line of a transformer limited the peak value of initial fault current, while the normal conductor finally limited the fault current. In order to secure the operating reliability of transformer type Superconducting Fault Current Limiter (SFCL) of previously proposed structure, we analyzed the operating characteristics according to the fault types. We tested a line-to-ground fault and a line-to-line fault. As a result of the experiment, all the faults showed that the superconductor stably limited the peak-value of initial fault current. Also, the normal conductor finally limited the fault current. Based on this research results, We thought that if the structure of inserting superconductor into the neutral line is applied to the real system, it could improve the reliability and stability of the power system.
$2{\times}3$구조의 매트릭스형 초전도 한류기의 트리거 코일 및 션트 저항에 따른 특성
정병익,최효상,Jung, Byung-Ik,Choi, Hyo-Sang 대한전기학회 2009 전기학회논문지 P Vol.58 No.1
We investigated the quench characteristics in accordance with increase of turns number of trigger coil and shunt resistance of matrix-type superconducting fault current limiter (SFCL) with $2{\times}3$ array. The matrix-type SFCL consists of the trigger part to apply magnetic field and the current-limiting part to limit fault current. The fault current limiting characteristics according to the increase of magnetic field and applied voltage were nearly same. This is because the application of magnetic field hasn't an affect on total impedance of the SFCL. When turns number of a reactor increased, the voltage difference between two superconducting units in the current-limiting part according was decreased. The resistance difference generated in two superconducting units was also decreased. Therefore, we confirmed that the differences of the critical behaviors between superconducting units were reduced by application of magnetic field. By this results, we could decide the optimum turns number of reactor to apply magnetic field.
2×3구조의 삼상 매트릭스형 초전도 한류기의 고장 유형에 따른 동작특성 비교
정병익(Byung-Ik Jung),조용선(Yong-Sun Cho),최효상(Hyo-Sang Choi),정동철(Dong-Chul Chung),황종선(Jong-sun Hwang) 대한전기학회 2009 대한전기학회 학술대회 논문집 Vol.2009 No.7
매트릭스형 초전도 한류기는 구조의 특성상 여러개의 초전도 소자가 삽입되게 되었다. 이러한 여러개의 초전도 소자들 중 어느 한개가 열화되거나 고장이 발생했을때 한류 동작이 정상적으로 이루어지지 않는다면 안정성면에서 신뢰성을 얻기는 힘들 것이다. 따라서 본 논문에서는 직?병렬로 연결된 초전도 소자의 고장 소자의 위치에 따른 한류기의 동작특성을 비교 분석하였다. 삼상 매트릭스형 초전도 한류기의 trigger part와 current-limiting part의 초전도 소자 단선시 사고전류 제한 특성과 정상동작하는 초전도 소자의 전압특성을 비교 분석하였다.
정병익(Byung-Ik Jung),최효상(Hyo-Sang Choi),조용선(Yong-Sun Cho),이주형(Joo-Hyoung Lee),정수복(Su-Bok Jung),오금곤(Kum-Gon Oh) 한국조명·전기설비학회 2008 한국조명·전기설비학회 학술대회논문집 Vol.2008 No.10월
We investigated a flux-coupling type superconducting fault current(SFCL) limiter. The SFCL consisted of the primary and secondary coils, which were wound in series each other through an iron core. Superconducting unit was connected with secondary coil in parallel. The flux generated from a coil in normal operation is cancelled out by its structure and the zero resistance of the superconducting unit. In this paper, In order to compare the current limiting effects of the SFCL by applied voltage. When applied voltage was increased, quench time was shortened. Fast quench time is important component under the same fault condition because power burden of the SFCL is reduced by that of the superconducting units. The current limiting behavior of flux-coupling type SFCL was dependent upon the applied voltage.
1선 지락시 3상 자속결합형 초전도 한류기의 동작특성 분석
정병익(Byung-Ik Jung),최효상(Hyo-Sang Choi),조용선(Yong-Sun Cho),하경훈(Kyoung-Hun Ha),최수근(Soo-Gun Choi),김덕구(Duck-Gu Kim) 한국조명·전기설비학회 2010 한국조명·전기설비학회 학술대회논문집 Vol.2010 No.5월
현대의 전력사용 증가와 망상구조의 계통 구조로 인해서 사고시 사고전류로 인한 피해가 중가하고 있다. 계통의 사고 대책으로 여러 가지 방안들이 연구되고 있다. 본 논문에서는 초전도 소자와 변압기를 이용한 자속결합형 초전도 한류기를 이용한 사고전류 제한 실험을 실시했다. 삼상 계통에서 1선 지락사고시 계통의 사고전류 제한 특성을 분석하였다. 1선 지락사고시 정상 상에 연결된 초전도 소자에서도 ?치가 발생하는 것을 확인할 수 있었다. 이것은 각 상과 연결된 리액터가 하나의 철심을 공유하기 때문으로 사료된다. 사고시 전력 부담은 변압기와 초전도 소자가 나누워 부담함으로써 초전도 소자의 부담을 감소시킬 수 있었다.
2.4/5GHz 이중대역 RF 설계 및 구현과 성능 평가
정병익(Byung-Ik Jung),석경휴(Gyeong-Hyu Seok) 한국전자통신학회 2023 한국전자통신학회 논문지 Vol.18 No.5
본 논문에서는 기존 2.4GHz 대역을 이용한 무선 AV 감시시스템의 신뢰성과 안정성을 확보하기 위해서 2.4/5GHz 이중대역을 사용하였다. 제안된 시스템은 타신호(Wifi, Bluetooth 등)로부터 간섭을 회피하기 위해 동적 채널할당 및 채널 변경기술을 지원하고, 무선 CCTV 구축시 발생되는 유지 보수 비용을 절감 시키며 기존 유선 CCTV와 연동 가능해져 CCTV를 이용한 A/V 감시시스템의 서비스 영역을 확대할 수 있다. In this paper, the 2.4/5GHz dual band was used to ensure the reliability and stability of the wireless AV surveillance system using the existing 2.4GHz band. The proposed system supports dynamic channel allocation and channel change technology to avoid interference from other signals (Wifi, Bluetooth, etc.), reduces maintenance costs incurred when building wireless CCTV, and can be linked with existing wired CCTV. The service area of the A/V surveillance system used can be expanded.
삼상 변압기와 전력용 스위치를 이용한 초전도 한류기의 과도특성 해석
정병익(Byung-Ik Jung),최효상(Hyo-Sang Choi),박정일(Jung-Il Park),조금배(Geum-Bae Cho) 대한전기학회 2012 전기학회논문지 Vol.61 No.11
The research of superconducting fault current limiter (SFCL) for reduction of the fault current is actively underway in the worldwide. In this paper, we analyzed the characteristics of a SFCL using the transformer and superconducting elements combined mutually in accordance with the fault types. The structure of this SFCL was composed of the secondary and third windings of a transformer connected to the load and the superconducting element, respectively. The provided electric power flew into the load connected to the secondary winding of the transformer in normal state. On the other hand, when the fault occurred in power system, the fault current was limited by closing the line of third winding of the transformer. At this time, the effect of the fault was minimized by opening the fault line in secondary winding of a transformer in power system. The sensing of the fault state was performed by the current transformer(CT) and then turn-on and turn-off switching behavior of the secondary line in the transformer was performed by the silicon-controlled rectifier(SCR). As a result, the proposed SFCL limited the fault current within one-cycle efficiently. Also, the degradation of the superconducting element in the normal state was avoided.