• Title/Summary/Keyword: 직류차단기

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Hybrid LVDC Circuit Breakers (저압직류용 하이브리드 차단기)

  • Hyo-Sung, Kim
    • The Transactions of the Korean Institute of Power Electronics
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    • v.27 no.6
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    • pp.489-497
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    • 2022
  • This work investigates the commutation characteristics of the current flowing through an electrical-contact-type switch to the semiconductor switch branch during the breaking operation of hybrid DC switchgear. A simple, reliable, low-cost natural commutation method is proposed, and the current commutation characteristics are analyzed in accordance with the conduction voltage drop of the semiconductor switch branch through experiments. A prototype 400 V/10 A class natural commutation type hybrid DC switchgear is set up. Its performance is verified, and its characteristics are analyzed.

28 GHz 초전도 ECRIS의 마이크로파 전파 특성 및 이를 이용한 시스템 설계

  • Wang, Seon-Jeong;Won, Mi-Suk;Lee, Byeong-Seop;An, Chan-Yong;Kim, Seon-Ho;Gwak, Jong-Gu;Jeong, Seung-Ho;Kim, Seong-Gyu
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.08a
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    • pp.134-134
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    • 2010
  • KBSI 부산센터에 건설중인 소형의 다중 양전하 중이온 가속기에 사용될 초전도 ECR 이온온은 최대 자기장 3 T, 최소 0.5 T의 자기 Mirror구조를 가지고 있으며 중심 부근의 1 T 자기장에서 28 GHz 전자공명에 의해 마이크로파의 에너지를 플라즈마로 전달한다. 최대 10 kW의 Gyrotron에서 TE02 모드로 발생하는 마이크로파는 모드변환기, 직류차단기 및 진공창을 통하여 플라즈마로 입사된다. 32.5 mm 지름의 원형 도파관에서 자기장 축방향으로 도입된 TE01 모드의 마이크로파를 Altar-Appleton-Hartree 분산관계식을 이용하여 군속도의 관점에서 살펴보았다. 플라즈마 밀도가 Cut-off에 근접하지 않는 한 마이크로파의 바깥 방향으로의 회절은 크지 않았으며, 전자공명 위치로 접근함에 따라 군속도의 방향이 바뀌어 오히려 중심 방향으로 향함을 알 수 있다. 즉 마이크로파가 플라즈마 챔버의 벽을 가열시킬 가능성은 크지 않은 것이다. 또한 뜨거운 전자 플라즈마의 Susceptibility를 이용하여 마이크로파의 플라즈마로의 전자 공명에 의한 흡수를 살펴본 결과, 운전 영역에 속하는 전자밀도가 제공되면 공명 지점에 이르기 전에 충분히 흡수되는 것을 확인하였으며, 이에 따라 챔버를 관통하여 인출부 벽에 충돌하는 마이크로파 에너지는 무시할 수 있을 것으로 보여진다. 이 결과들을 토대로 마이크로파 시스템을 설계 완료하였다.

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Arc Extinguishment for Low-voltage DC (LVDC) Circuit Breaker by PPTC Device (PPTC 소자를 사용한 저전압 직류차단기의 아크소호기술)

  • Kim, Yong-Jung;Na, Jeaho;Kim, Hyosung
    • The Transactions of the Korean Institute of Power Electronics
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    • v.23 no.5
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    • pp.299-304
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    • 2018
  • An ideal circuit breaker should supply electric power to loads without losses in a conduction state and completely isolate the load from the power source by providing insulation strength in a break state. Fault current is relatively easy to break in an Alternating Current (AC) circuit breaker because the AC current becomes zero at every half cycle. However, fault current in DC circuit breaker (DCCB) should be reduced by generating a high arc voltage at the breaker contact point. Large fire may occur if the DCCB does not take sufficient arc voltage and allows the continuous flow of the arc fault current with high temperature. A semiconductor circuit breaker with a power electronic device has many advantages. These advantages include quick breaking time, lack of arc generation, and lower noise than mechanical circuit breakers. However, a large load capacity cannot be applied because of large conduction loss. An extinguishing technology of DCCB with polymeric positive temperature coefficient (PPTC) device is proposed and evaluated through experiments in this study to take advantage of low conduction loss of mechanical circuit breaker and arcless breaking characteristic of semiconductor devices.

Simulation for characteristics of various type SFCLs (유형별 초전도 한류기의 특성에 대한 시뮬레이션)

  • Choi, Hyo-Sang;Hyun, Ok-Bae;Kim, Sang-Joon;Han, Byoung-Sung
    • 한국초전도학회:학술대회논문집
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    • v.9
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    • pp.338-342
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    • 1999
  • We simulated the current limiting characteristics of resistive and inductive SFCLs with 100 ${\omega}$ of impedances for a single and double line-to-ground faults in the 154 kV grid between two substations nearby Seoul. The transient current at the faults includes not. only high AC current up to 44 kA but also significant DC component as high as 4 kA. The DC current is greater and lasts longer for the double line-to-ground fault than for the single line-to-ground fault. The inductive SFCL limited the fault current more effectively than the resistive one. The DC component, however, was greater and diminishes slower for the inductive SFCL than for the resistive one.

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Analysis of Switching Surge Over-voltage in AC/DC Hybrid Transmission Lines (AC/DC 병가선로의 개폐서지 과전압 해석)

  • Yoo, Seong-Soo;Shin, Koo-Yong;Moon, Chae-Joo
    • The Journal of the Korea institute of electronic communication sciences
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    • v.17 no.3
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    • pp.459-466
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    • 2022
  • Switching surges are a common type of phenomenon that occur on any sort of power system network. These are more pronounced on long transmission lines and in high voltage converter stations. At AC/DC hybrid transmission lines, the insulation coordination of such lines is mainly dictated by the peak level of switching surges, the most dangerous of which include three phase line energization and AC/DC converter station. The power system structure consist of AC/DC hybrid transmission lines which is combination of AC 765kV and ±500kV HVDC 1 bipole system for contingency analysis. The power system under study and its components are simulated using EMTDC software package, the effects of the various AC/DC mixing power lines are reviewed. The developed models of EMTDC conversion lines based on combination of AC/DC system are simulated and the characteristics of switching surge over-voltage from its results are discussed.

Design Optimization Simulation of Superconducting Fault Current Limiter for Application to MVDC System (MVDC 시스템의 적용을 위한 초전도 한류기의 설계 최적화 시뮬레이션)

  • Seok-Ju Lee
    • Journal of Korea Society of Industrial Information Systems
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    • v.29 no.3
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    • pp.41-49
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    • 2024
  • In this paper, we validate simulation results for the design optimization of a Superconducting Fault Current Limiter (SFCL) intended for use in Medium Voltage Direct Current systems (MVDC). With the increasing integration of renewable energy and grid connections, researchers are focusing on medium-voltage systems for balancing energy in new and renewable energy networks, rather than traditional transmission or distribution networks. Specifically, for DC distribution networks dealing with fault currents that must be rapidly blocked, current-limiting systems like superconducting current limiters offer distinct advantages over the operation of DC circuit breakers. The development of such superconducting current limiters requires finite element analysis (FEM) and an extensive design process before prototype production and evaluation. To expedite this design process, the design outcomes are assimilated using a Reduced Order Model (ROM). This approach enables the verification of results akin to finite element analysis, facilitating the optimization of design simulations for production and mass production within existing engineering frameworks.

Equivalent three-phase synthetic making test for medium voltage circuit breaker of distribution system using DC power (직류전원을 이용한 배전급 차단기의 등가 3상 합성투입시험법)

  • Park, Byung-Rak;Jo, Man-Yong;Kim, Jin-Seok;Shin, Hee-Sang;Kim, Jae-Chul
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.25 no.7
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    • pp.105-113
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    • 2011
  • The study about three-phase synthetic making test using DC power has been performed in order to increase the making test capacity on Vacuum Circuit Breaker. And, it made possible to solve the limitations that short-circuit testing facilities can not fulfill the testing requirements of VCB exceeding three-phase 36[kV] 31.5[kA]. By using DC power and high speed spark-gap switch, this method made the equivalence with the pre-arc that occurred during the making process under the fault condition of power system. As results, KERI(Korea Electrotechnology Research Institute) could have capacity to carry out type test for VCB under three-phase 52[kV] 40[kV], which satisfies the IEC Standard.

A Study on DC Circuit Breaker using SCR Chung Hoo Park (SCR 에 의한 직류회로차단기의 과부하차단특성개선)

  • 박정후
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.14 no.2
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    • pp.89-95
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    • 1978
  • A SCR static breaker was studied on the Resistive and inductive load, then on the overload break circuit using operational Amplifier. In this paper, the principal circuit required for forced commutation was voltage commutation by the introduction of a parallel Capacitor. The results obtained are follows; 1. In thecondition that the tima constant of R-C circuit is larger than the turn off time of SCR, the breaker has low transient phenomena and no recovery vol age. 2. By using OP Amplifier on the load circuit, overcurrent trip point will be able to adjust to the wide range of over current. 3. In the over current qrcuit, the power loss was reduced remarkably.

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The Characteristic Study for Small Current Breaking of High Speed DC Circuit Breaker (직류고속도차단기의 소전류 차단 특성연구)

  • Min Byung-Hoon;Jang Woo-Jin;Ko In-Suk
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.55 no.8
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    • pp.396-402
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    • 2006
  • Even the case DC circuit Breaker have good quality for interruption of high current like heavy load current, short-circuit current, the verification for small current breaking capability of circuit breaker should be performed. It comes from the reason DC small current breaking failure can be lead to break out second heavy fault condition and in the long run substation shutdown. In this paper, we can find the characteristics of DC small current and international test standard discription about small current breaking and one of the proper solution to get over it.

A Study on the DC High Speed Circuit Breaker(HSCB) in Electric Railway Substation System (전기철도 변전소의 직류고속도차단기 동작 감소방안에 관한 연구)

  • Heo, Tae-Bok;Kim, Hak-Lyun;Chang, Sang-Hoon
    • Proceedings of the KSR Conference
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    • 2004.10a
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    • pp.1303-1308
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    • 2004
  • This paper proposes a reduction method for the mis-operation analysis of the DC High Speed Circuit Breaker(HSCB) in electric railway substation system. The analysis method is based on present condition of operation which is a method for accuracy level up. There is reason to operation of HSCB that it is mis-operation of fault detection relay(50F), operation of ground fault relay(64P), and trouble of electric car. A countermeasure is relay resetting through field test, induction of GTOCB(Gate Turn Off Thyristor Circuit Breaker), HSVCB(High Speed Vacuum Circuit Breaker), coordination with electric car. The results presented in the paper can be used as a reference for maintenance free in electric railway substation system.

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