• 대한전기학회논문지:전력기술부문A
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• 제54권5호
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• pp.212-216
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• 2005

This paper describes the application scheme of resistive HTS-FCL(High Temperature Superconducting-Fault Current Limiter) on future new distribution system. Future new distribution system means the power system to which applies the 22.9kV HTS cable with low-voltage and mass-capacity characteristics replacing the 154kv conventional cable in addition to HTS transformer and HTS-FCL. The fault current of future new distribution system will increase greatly because of the inherent characteristics of HTS transformer/cable and applications of distributed generations and spot networks and so on. This means that the HTS-FCL is necessary to reduce the fault current below the breaking capacity. This paper studies the appropriate location, parameters and the influences of HTS-FCL on future new distribution system. Finally, this paper suggests the reasonable basic parameters of resistive HTS-FCL for future KEPCO new distribution system.

• 한국초전도ㆍ저온공학회논문지
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• 제12권2호
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• pp.17-20
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• 2010

A considerable amount of research material discussing designs and properties of High Temperature Superconducting Fault Current Limiter (HTS FCL) is available. However, a shortage of research concerning positioning of HTS FCL in power grid is felt. In this paper a feasibility study of HTS FCL positioning in Smart Grid through simulation analysis is carried out. A complete power network (including generation, transmission and distribution) is modeled in Simulink / SimPowerSystems. A generalized HTS FCL is also designed by integrating Simulink and SimPowerSystem blocks. The distribution network of the model has a wind turbine attached to it forming a micro grid. Three phase fault have been simulated along with placing FCL models at key points of the distribution grid. It is observed that distribution grid, having distributed generation sources attached to it, must not have a single FCL located at the substation level. Optimized HTS FCL location regarding the best fault current contribution from wind turbine has been determined through simulation analysis.

• 전자공학회논문지A
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• 제31A권10호
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• pp.1-9
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• 1994

In this paper, we have studied optimal FCL(Frequently Called List) table sizes in a grid topology circuit-switched network including wireless subscribers. The FCL table gives the position information of a destination subscriber for a call. When the call is generated in a node, this call is routed by the referenced position information of the destination subscriber in FCL table. In this paper, we have proposed an efficient routing algorithm, mixed FSR(Flood Search Routing) and DAR(Dynamic Adaptive Routing), considering moving wireless subscribers. Also, we have simulated hit ratio and incorrect ratio as performance parameters, consequently proposed the object function composed of table search time, hit ratio, incorrect ratio, FSR time and DAR time, and derived the optimal FCL table size by using it.

• 한국초전도ㆍ저온공학회논문지
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• 제15권3호
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• pp.24-28
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• 2013

Fault current limiting (FCL) cable is a kind of superconducting cable which has a function of limiting the fault current at the fault of power grid. The superconducting cable detours the fault current through its stabilizer to keep the temperature as low as possible. On the other hands, the FCL cable permits the temperature rise within some acceptable limit and the fault current is limited by the consequent increase of the resistance of superconducting cable. This kind of FCL cable is called 'resistive FCL cable' because it uses resistive impedance to limit the fault current. In this paper, we suggest a novel concept of FCL cable, which is named as 'inductive FCL cable'. The inductive FCL cable is similar as the magnetic shielding fault current limiter in its operating mechanism. The magnetic field of superconducting cable is almost perfectly shielded by the induced current at the shielding layer during its normal operation. However, at the fault condition, quench occurs at the shielding layer by the induced current higher than its critical current and the magnetic field is spread out of the shielding layer. It will induce additional inductive impedance to the superconducting cable and the inductive impedance can be increased more by installing some material with high magnetic susceptibility around the superconducting cable. We examined the feasibility of inductive FCL cable with simple elemental experiments. The current limiting performance of inductive FCL cable was estimated considering an arbitrary power grid and its fault condition.

• 대한기계학회논문집A
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• 제34권9호
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• pp.1185-1191
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• 2010

장기운영된 항공기에는 비행시간의 누적에 따라 다양한 피로균열이 발생하며 이는 운영상 안전성 및 가동률을 저하시키는 요인이 된다. 이의 해결을 위하여 피로임계위치(Fatigue critical location, FCL)에 대한 균열 진전 해석은 매우 중요하다. 그러나 이러한 장기 운영된 항공기의 경우, 균열 진전 해석에 필수적인 FCL에서의 응력 스펙트럼 획득은 거의 불가능한 실정이다. 본 연구에서는 장기운영된 항공기 주익 구조물의 FCL에서의 균열 진전 해석을 수행하기 위하여, 먼저 주익 구조물에 대한 2차원 하드카피 형태의 도면으로부터 구축된 3차원 CAD 모델에 대한 유한요소해석을 수행하였다. 또한 이러한 유한요소해석 결과 및 제한된 하중배수 자료를 기반으로 FCL에서의 전달함수와 응력 스펙트럼을 산출하였다. 상기 자료를 바탕으로 상용 균열 진전 해석 코드인 NASGRO를 이용하여 FCL에서의 균열진전해석을 수행하였다.

• 한국전기전자재료학회논문지
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• 제11권12호
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• pp.1139-1145
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• 1998

In this paper, to fabricate a superconducting fault current limiter(FCL) of thick film type, $YBa_2Cu_3O_X superconducting thick films were fabricated by surface diffusion process using the screen printing method. Powder mixture of $3BaCuO_2$+2CuO was screen printed on $Y_2BaCuO_5$(d=15mm). And critical current densities of the thick films were observed as the sintering temperature(92$0^{\circ}C$~95$0^{\circ}C$) and holding time(2h~10h). Based on experimental data, the thick films for superconducting FCL were sintered at $940^{\circ}C$ in 2 hours. The superconducting FCL with a current limiting area of 1mm wide and 66mm long was prepared on $Y_2BaCuO_5$ substrate. To measure the characterization of the fabricated FCL, an alternating voltage (60Hz) was applied to the FCL in 77K liquid nitrogen. At an applied voltage of 4V, the FCL was limited from 20A into 0.6A not farther than 0.5ms.

• 한국초전도ㆍ저온공학회논문지
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• 제8권1호
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• pp.49-53
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• 2006

This paper specifies the new power supply paradigm converting 154kV voltage level into 22.9kV class with equivalent capacity using superconducting rower facilities and analyze the fault current characteristics with and without HTS-FCL (High Temperature Superconducting-Fault Current Limiter). Superconducting new power system is the power system to which applies the 22.9kV HTS cable in parallel to HTS transformer and HTS-FCL with low-voltage and mass-capacity characteristics replacing 154kV conventional cable and transformer. The fault current of superconducting new power system will increase greatly because of the mass capacity and low impedance of HTS transformer and cable. This means that the HTS-FCL is necessary to reduce the fault current below the breaking current of circuit breaker. This paper analyze the fault current and suggests the parallel HTS-FCL scheme complementing the inherent problem of HTS-FCL, that is recovery after quenching is impossible within shorter than a few seconds.

• 한국초전도ㆍ저온공학회논문지
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• 제5권3호
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• pp.26-29
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• 2003

Nowadays, one of the serious problems in KEPCO system is much higher fault current than the SCC(Short Circuit Capacity) of circuit breaker. As the superconductivity technology has developed, the HTS-FCL(High Temperature Superconductor-Fault Current Limiter) can be one of the attractive alternatives to solve the fault current problem. But the parameters of HTS-FCL should be designed optimally to have the best performance. Under this background, this paper presents the optimal design method of parameters for resistive type HTS-FCL using Monte Carlo technique.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1034-1035
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• 2015

Watertight 25.8 kV/600 A/12.5 kA fault current limiters (FCLs) have successfully installed in five areas (Incheon, Seoul, Gyeong-gi, Daejeon, Suwon) on KEPCO power distribution line for the purpose of commercial demonstrations. The fault current limiting operation of this FCL, which includes functions of sensing, commutation, and reduction of fault currents, is perfectly completed within 1 cycle immediately after fault occurs. The performance of FCL was verified by short circuit test, impedance test, insulation test, temperature-rise test, and control test, etc at PT&T in LS industrial systems, which is the official certification institute in Korea. In 2013, and also the FCL field test was performed in order to test the protection coordination between conventional relays and FCL, on the 1.5 kA and 5.0 kA faults, which were made by connecting the Artificial Fault Generator (AFG) to the distribution line in test grid at KEPCO Power Testing Center. The next step of this project is to check the FCL conditions caused by real external environment, and acquire the various data from five regions installed with FCL. In this paper, we intend to explain the FCL specifications and performance characteristics, and check the expected effect by application of FCL to power distribution line based on the power system analysis of an application site.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2001년도 학술대회 논문집
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• pp.68-71
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• 2001

This paper deals with the operational characteristics of the three-phase modified bridge type fault current limiter(FCL) for 3.3kV/200A power system. This is a preliminary step to develop the FCL's faculties for an application to high voltage transmission line. A three-phase modified bridge type FCL consists of transformers, diodes, and a high-Tc superconducting coil. As the results of simulations, when the FCL of 1.5H inductance was installed in the power system. the fault current was reduced to be about 90% of that without FCL.