• 한국초전도ㆍ저온공학회논문지
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• 제19권2호
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• pp.44-47
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• 2017

In this paper, the current limiting characteristics of the transformer type superconducting fault current limiter (SFCL) with the two coupled secondary windings due to its winding direction were analyzed. To analyze the dependence of transient fault current limiting characteristics on the winding direction of the additional secondary winding, the fault current limiting tests of the SFCL with an additional secondary winding, wound as subtractive polarity winding and additive polarity winding, were carried out. The time interval of quench occurrence between two superconducting elements comprising the transformer type SFCL with the additional secondary winding was confirmed to be affected by the winding direction of the additional secondary winding. In case of the subtractive polarity winding of the additional secondary winding, the time interval of the quench occurrence in two superconducting elements was shorter than the case of the additive polarity winding.

• 산업경영시스템학회지
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• 제2권2호
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• pp.5-10
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• 1979

For investment calculation of capital assets, it is desirable to grasp the limiting factors of its calculation. The limiting factors can be listed as follows; $\circled1$ difficulty in estimating the service life of capital assets. $\circled2$ difficulty in estimating the receipts, and operating and maintenance expenses of the project. $\circled3$ difficulty in determining common Minimum Attractive Rate of Return. $\circled4$ difficulty in estimating the salvage value of the assets. $\circled5$ some limiting factors on present worth calculation of the projects. $\circled6$ Some limiting factors on payout period method of the economic calculation.

• 한국전기전자재료학회논문지
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• 제30권1호
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• pp.37-41
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• 2017

In this paper, the fault current limiting characteristics of the flux-lock type SFCL (superconducting fault current limiter) using magnetic application circuit were analyzed. The flux-lock type SFCL has the structure to install the magnetic application circuit, which can increase the resistance of HTSC ($high-T_C$ superconducting element comprising) the SFCL. To analyze the fault current limiting effect of the flux-lock type SFCL through the magnetic flux application circuit, the flux-lock type SFCL either with the magnetic flux circuit or without the magnetic flux circuit was constructed and the fault current limiting characteristics of the SFCL were compared each other through the short-circuit tests.

• Progress in Superconductivity
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• 제3권2호
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• pp.235-240
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• 2002

In this paper, we investigated the current limiting characteristic in the magnetic shielding type fault current limiter(MSFCL). The circuit analysis was executed by using finite differential method(FDM). This paper suggests that the current limiting performance can be achieved in two ways (resistive and inductive one), according to design parameter. By comparing current limiting characteristics in two ways and surveying the important parameters which determine the operational way after fault occurs in the design of MSFCL, it is shown that the magnetic shielding type fault current limiter can be operated in either resistive or inductive way.

• 한국초전도ㆍ저온공학회논문지
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• 제21권4호
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• pp.39-43
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• 2019

The breaking of a circuit in DC grid could pose a challenge because of the absence of zero-crossing instant for both current and voltage when a fault occurs. An additional fault current limiting function will be very helpful for reducing the burden of the DC circuit breaker by limiting the fault current to a reasonable value. In this paper, we studied the overcurrent characteristics of several HTS conductors so that we could use the selected conductors for the basic design work of a resistive type fault current limiting module as a part of the circuit breaking system. According to the short-circuit test results, we suggested and compared two different basic design parameters of the HTS fault current limiting module, which will be connected in series to the DC circuit breaker.

• 조명전기설비학회논문지
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• 제28권7호
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• pp.62-68
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• 2014

We proposed a series connection-type superconducting fault current limiter(SFCL) using E-I core that can prevent the internal magnetic flux generation of cores during normal operation, and prevent the saturation of cores due to a sudden magnetic flux generation at the initial stage of fault occurrence while limiting the peak current. Through a short-circuit simulation experiment, we analyzed the operating status of the two superconducting elements and limiting characteristics according to the size of the fault current peak before and after the failure. Further, the double peak current limiting characteristics according to the winding directions as well as the current and the voltage of each coil were compared and analyzed.

• Bulletin of the Korean Chemical Society
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• 제10권5호
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• pp.414-418
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• 1989

The electrochemical behavior of cadmium(Ⅱ) in tartrate solution has been studied over the pH range of 6 to 13.6 in order to explain the phenomena of the changes in limiting current depending on the pH. The polarographic limiting current showed a constant value up to pH of 7.8, after which it decreased sharply to show a minimum at pH between 11 and 12. The limiting current, then, increased again with increasing pH. The number of peaks in cyclic voltammogram was 1 to 3 depending on the pH of the solution. Two other voltammetric peaks could be observed when the main reduction peak diminished. The decrease of limiting current at 7.5$Cd(C_4H_3O_6)^-$. The increase of limiting current at strong alkaline solution, however, was due to the complex $Cd(Tart)_2(OH)_2^{4-}$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.371-371
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• 2009

For the application of superconducting wires to fault current limiting devices, it is required that they have a high rated voltage when a fault occurs. Stabilizer-free coated conductors, particularly, shows a good performance for the high rated voltage, which is beyond 0.6 V/cm. In this study, using the stabilizer-free coated conductors, we made fault current limiting devices and examined their characteristics. Fault current limiting devices were fabricated with a shape of the cylinder of a mono-filar coil winding. Stabilizer-free coated conductors were wound along the mono-filar coil line and the terminal parts between the wire and metal were soldered using In solder. Two kinds of devices were fabricated by a different method in the terminal joint, one was made by a soldering and the other was made by a soldering-free joint. Critical currents and resistance at the joint parts were measured. In addition, long-time current flowing tests were also carried out for the characterization of the fault current limiting devices.

• 조명전기설비학회논문지
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• 제25권2호
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• pp.137-142
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• 2011

In this paper, the fault current limiting and the hysteresys characteristics of a superconducting fault current limiter (SFCL) using magnetic coupling of two coils on the iron core with an air-gap were analyzed. The introduction of the air-gap in the SFCL with magnetically coupled two coils can suppress the saturation of the iron-core and, on the other hand, make the limiting impedance of the SFCL decreased, which results from the increase of the exciting current. To analyze the effect of the aig-gap on the fault current limiting characteristics of the SFCL, the hysteresys curves of the iron core comprising the SFCL were derived from the short-circuit experiment and the variation in the voltage-current trace of the SFCL during the fault period was analyzed. Through the comparison with the current limiting characteristics of the SFCL without air-gap, the air-gap could be confirmed to contribute to the suppression of the iron core's saturation through the increase of the SFCL's burden from the short-circuit current.

• 한국항공우주학회지
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• 제34권7호
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• pp.1-11
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• 2006

본 논문에서는 불연속면이 포함된 다차원 유동에서 흔히 발생하는 수치적 진동현상을 막기 위해 기존의 TVD 제한자를 분석함으로써 새로운 형태의 다차원 제한 함수를 유도하였다. MLP 기법은 유도된 다차원 제한 함수를 기반으로 하며, 다차원 불연속면에서의 수치 진동을 효과적으로 제거하고 동시에 3차 이상의 공간 정확도 내삽기법과 함께 사용할 수 있다는 장점을 갖는다. 또한, 정상 유동의 경우 수치 진동이 제거됨으로써 수렴성이 향상됨을 확인할 수 있었고, 실제 코드에 적용하는 방법도 간단하다. MLP 기법을 적용함으로써 불연속 유동 뿐 만 아니라 연속 유동에서도 정확성, 효율성, 강건성 면에서 향상된 결과를 얻을 수 있음을 여러 가지 수치 실험을 통하여 확인하였다.