• Progress in Superconductivity
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• 제12권1호
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• pp.23-26
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• 2010

A double line commutation (DLC) type SFCL with first peak limiting function has been proposed for ideal fault current limiting operation. Very fast switching (commutation) without any arc or high voltage problems for any kind of switching device is needed for the first peak current limiting. We've tried to find suitable conditions for a successful switching of a Vacuum Interrupter (VI) with HTS elements as a Peak Current limiting Resistance (PCR).

• 한국초전도ㆍ저온공학회논문지
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• 제9권3호
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• pp.57-61
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• 2007

The current limiting characteristics of hybrid SFCL with additional power electronic devices was investigated in order to improve operation reliabilities. The hybrid SFCL developed consists of a superconducting trigger (S/T) part, a fast switch (F/S) module and a current limiting (C/L) part. Although hybrid SFCL had shown a excellent current limiting characteristics, this device was rather vulnerable to the residual arc currents which could exist during fast switch operation. This undesirable arc should be extinguished as quickly as possible in order to implement perfect fault current commutation. So, in order to eliminate the residual arcs between fast switch contacts, the power electronic devices (IGBT or GTO) were connected in series between the S/T part and the interrupter of the F/S module. According to the fault tests conducting with an input voltage of $270\;V_{rms}$ and a fault current of $5\;kA_{rms}$, The power electronic devices could perfectly remove the arc generated between the contacts of the interrupter within 4 ms after the fault occurred. From the test analysis, it was confirmed that the hybrid SFCL could enhance the operation reliability by adopting additional power electronic devices.

• 전기학회논문지
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• 제68권1호
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• pp.215-219
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• 2019

Development of DC interruption technology is being studied actively for enhanced DC grid reliability and stability. In this study, coil type superconductor DC circuit breaker was proposed as DC interruption. It is integration technology that combined current-limiting technique using superconductor and cut-off technique using mechanical DC circuit breaker. Superconductor was applied to the coil type. In simulation, Mayr arc model was applied to realize the arc characteristic in the mechanical DC circuit breaker. PSCAD/EMTDC had used to model and perform the simulation. To find out the protection range of coil type superconductor DCCB, the working operation have analyzed based on the rated voltage of DCCB. The results confirmed that, according to apply the limiting device, the protection range was increased in twice. Therefore, the probability of failure of interruption has lowered significantly.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.144-146
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• 2002

The latest development flow of MCCB(Molded Case Circuit Breaker) is largely separated from which are high capability of interrupting compact of size and multi-ability in functions. As follow of development of industrial system. MCCB which are including communication function and having a ultimate interrupting capability is required in electrical system. to attain an effective limitation of the peak let-through current and the let-through energy, the arc has to move rapidly off the contacts and has to increase the arc voltage which mainly effect to interrupt. In this paper. we made high performance circuit breaker which including current limiting unit which is attached to the main which is simulated by CAE tool that are repulsion force and mechanical dynamics after that we tested and finally selected optimized for circuit breaker.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1540-1541
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• 2006

For limitation and interruption of short circuit currents from low voltage to extra high voltage applications, the electrical equipment including fuses and circuit breakers, are widely used today. But in order to anticipate increasing needs for effective and competitive device for limiting the growing fault current in electrical power systems, fault current limitation technologies and fault current limitation devices are widely introduced and investigated in these days. Fault current limiters are emerging electric equipment which is under development using various methods including superconducting fault current limiter, solid state fault current limiter, arc driving fault current limiters. And these various methods have some advantages and disadvantages to take into considerations In order to commercialize fault current limiters in the electrical networks, a lot of discussions should be given on the point that fault current limiting methods, need for fault current limiters, coordination with existing protective system, and field experience before commercialization. In this paper, recent trends of fault current limiting technologies will be reviewed and the key issues of superconducting fault current limiters will be dealt with. And finally, future applications of superconducting fault current limiters would be discussed.

• 전기학회논문지
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• 제67권7호
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• pp.981-986
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• 2018

AC(alternating current) CB(circuit breaker) at the fault occurred in the existing AC distribution system is limiting the fault current through zero cross-point. However, DC(direct current) CB does not have zero cross-point. Therefore, arc occurred by on-off operation of DC CB is very huge. Nowadays, many research team are studying the way to decrease breaking time, which is one of the essential conditions in DC CB. We suggested novel arc-induction type DC CB in this paper. The proposed arc-induction type DC CB is composed of the mechanical Arc ring and DC CB. We confirmed the operation of arc-induction type DC CB through the HFSS(High Frequency Structure Simulator) 3D simulation program and performed the experiment for operation characteristics. Results showed that arcing time of the arc-induction type DC CB by using induction ring was faster than existing mechanical DC CB. On the transient system, we confirmed stable operation characteristics of the arc-induction type DC CB through the simulation and experimental results. We expect that the proposed arc-induction type DC CB technology is will go to stay ahead of the existing DC CB technology.

• 한국산학기술학회논문지
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• 제21권3호
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• pp.129-136
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• 2020

컷아웃스위치(COS: Cut Out Switch 이하 COS)는 전력계통에서 수용가로 전력을 송배전하기 위해 사용되는 변압기의 입력단에 설치되어 사고전류로부터 변압기를 보호하기 위해 설치되는 보호장치이다. COS는 크게 퓨즈링크와 COS몸체 및 접속부로 구성되어 사고전류시 퓨즈링크의 엘리먼트가 용단되어 사고전류를 차단하는 역할을 한다. COS 퓨즈링크가 용단되어 발생하는 강력한 아크가 화염과 소음을 유발시켜 주변지역 거주자에게 불쾌감 및 공포감을 주며, 아크화염으로 인하여 주변기기의 2차 피해를 유발시킬 수 있다. 본 논문에서는 COS 동작 시 발생되는 아크와 소음 및 보호협조의 문제점을 해결하기 위해 폭발형이 아닌 한류형 COS 퓨즈를 개발하였다. 또한 과전류 차단 기능이 없는 한류형 퓨즈의 단점을 개선하기 위해 퓨즈 엘리멘트, 스트라이커와 COS 퓨즈금구 개발을 통하여 과전류 차단성능의 신뢰성을 향상시켰다. COS의 동작 특성 향상은 퓨즈 엘리멘트의 최적 형상 도출, 스트라이커의 원활한 동작을 위한 동작선의 재질과 두께 및 저항 산정, 그리고 스트라이커와 연계된 하부금구류의 구조 개선을 통하여 수행하였다. 본 연구에서 개발한 COS 퓨즈링크는 공인기관의 시험을 통하여 차단성능과 보호협조 성능을 검증하였다. 시험은 본 연구의 한류형 COS와 기존의 폭발형 비한류형 COS의 비교 시험으로 수행하였다.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제3B권4호
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• pp.165-172
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• 2003

Low voltage circuit breakers are widely used in power distribution systems to interrupt fault current rapidly and to assure the reliability of the power supply. This paper is focused on understanding the interrupting capability, more specifically of the contacts and the arc runner, based on the shape of the contact system in the current molded case circuit breaker (hereafter MCCB). Moreover, in order to improve the interrupting capability of the circuit breaker, the estimation and analysis of the interrupting capability, based on the 3-D magnetic flux analysis, were developed. Furthermore, this paper also presents results of the estimation and analysis of the interrupting capability when applied to different model breakers. In addition, this paper analyzes the efficiency of the interrupting tests by forming false current paths consisting of a three-division cascade arc runner in the contact system. With regards to the interrupting test, there is a need to assure that the optimum design required to analyze the electromagnetic forces of the contact system generated by the current and flux density be present. Based on the results of this study, this paper presents both computational analysis and test results for the newly developed MCCB 460V/225A/50㎄ contact system.

• 한국초전도ㆍ저온공학회논문지
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• 제19권4호
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• pp.40-44
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• 2017

This paper analyzed the fault current limiting characteristics of the previously proposed transformer superconducting fault current limiter (TSFCL) interruption system according to its transformer type. The TSFCL interruption system is an interruption technology that combines a TSFCL, which uses a transformer and a superconductor, and a mechanical DC circuit breaker. This technology first limits the fault current using the inductance of the transformer winding and the quench characteristics of the superconductor. The limited fault current is then interrupted by a mechanical DC circuit breaker. The magnitude of the limited fault current can be controlled by the quench resistance of the superconductor in the TSFCL and the turns ratio of the transformer. When the fault current is controlled using a superconductor, additional costs are incurred due to the cooling vessel and the length of the superconductor. When the fault current is controlled using step-up and step-down transformers, however, it is possible to control the fault current more economically than using the superconductor. The TSFCL interruption system was designed using PSCAD/EMTDC-based analysis software, and the fault current limiting characteristics according to the type of the transformer were analyzed. The turns ratios of the step-up and step-down transformers were set to 1:2 and 2:1. The results were compared with those of a transformer with a 1:1 turns ratio.

• Journal of Power Electronics
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• 제16권4호
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• pp.1298-1305
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• 2016

This paper presents the development of a short-circuit protection mechanism on a high voltage switch (HVS) board which is built by a series connection of semiconductor switches. The HVS board is able to quickly detect and limit the peak fault current before the signal board triggers off a gate signal. Voltage clamping techniques are used to safely turn off the short-circuit current and to prevent overvoltage of the series-connected switches. The selection method of the main devices and the development of the HVS board are described in detail. Experimental results have demonstrated that the HVS board is capable of withstanding a short-circuit current at a rated voltage of 10kV without a di/dt slowing down inductor. The corresponding short-circuit current is restricted to 125 A within 100 ns and can safely turn off within 120 ns.