• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2001.02a
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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.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 1999.02a
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• pp.101-105
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• 1999

We have performed an EMTDC simulation for the current limiting effects of a superconducting fault current limiter (SFCL). The fault currents in the 154 kV transmission line between the Gaepo and Sungnam substations increased up to 54kA and 60kA during the line-to-line and three phase faults, respectively. The SFCL with 100 $\Omega$ of impedance after quench limited the currents to less than 17 kA within a half cycle. This limited current is well below the upper limit of a circuit breaker, suggesting that the impedance of the SFCL in the transmission line is sufficient.

• Progress in Superconductivity and Cryogenics
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• v.1 no.2
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• pp.49-53
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• 1999

We fabricated a resistive superconducting fault current limiter (SFCL) with a shunt resistor in order to bypass the transient current at faults. The SFCL consists of a YBCO films coated with an Au layer (10$\Omega$ at room temperature). which is to disperse the heat generated at hot spots in the YBCO films, and a 5$\Omega$ shunt resistor. The minimum quench current of the SFCL was found to be 12.2Apeak. This SFCL successfully controlled the fault current to below 23 Apeak. Which is otherwise to increase up to 103 Apeak. With the shunt resistor, the temperature of the SFCL rose the temperature of the SFCL rose three times slower than without the shunt, whereby the SFCL is protected at high currents.

• Progress in Superconductivity and Cryogenics
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• v.13 no.3
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• pp.10-13
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• 2011

The power demand is steadily increasing due to rapidly develop of industrial field. The ratio of prospected increment of power consumption is over 2.2 % per year from 2007 to 2020 year. The superconducting fault current limiters(SFCLs) should be suggested to be one of promising machines to protect power grid. Four basis tests such as resistivity, short-circuit tests, ac losses and recovery time were investigated according to various reached maximum temperature, operating temperature. This paper deals with investigation of the various commercial high temperature superconductor for applying resistive type SFCLs.

• Progress in Superconductivity and Cryogenics
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• v.13 no.3
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• pp.14-18
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• 2011

Electrical system is changing to smart grid which includes the distributed generations with reusable energy sources in these days. The distributed generations are environmentally friendly and have no concern with depletion problem. But dispatching distributed generations can cause an increase of the fault current. Resistive type super conducting fault current limiter is one of the candidates of solution for the large fault problem in smart grid. In this paper, a design method for the wire length of fault current limiter and the result of short circuit test for small scale modules considering system resistance are introduced.

• Progress in Superconductivity and Cryogenics
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• v.5 no.2
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• pp.30-35
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• 2003

The inductive superconducting fault current limiter (SFCLJ limits the fault current with its dc reactor. To fabricate the optimal dc reactor for inductive SFCL, several design and manufacturing technologies are necessary. In this paper, the manufacturing technology for dc reactor and cryogenic cooling method are described in detail. GM-cryocooler was used enlarge the critical current of dc reactor by cooling down the temperature of dc reactor about 20 K. Moreover, the results of short circuit test were described. Finally, the thermal characteristics of conduction-cooled system were discussed and then, sub-cooled nitrogen system was proposed to enhance the thermal stability of dc reactor.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.9
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• pp.584-589
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• 2000

We fabricated resistive superconducting fault current limiters (SFCL) based on YBCO thin films grown on a 2-inch diameter Al2O3 substrate. The current limiting element was 1 mm wide and 260mm long meander line prepared by standard photolithography. The minimum quench current of the current limiting element was about 8 Apeak. This SFCL sucessfully controlled the fault current below 14.3 Apeak at the voltage of 100 Apeak which is otherwise to increase up to 141 Apeak. The quench completion time was less than 3 msec. The temperature of the current limiting element rose to about 200 K in 3 cycles after fault. The SFCL showed reproducible quench during hundreds times of repeated experiments.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.2
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• pp.73-79
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• 2004

Nowadays, one of the serious problems in KEPCO system is the larger fault current than the SCC(Short Circuit Capacity) of circuit breaker. There are many alternatives to reduce the increased fault current such as isolations of bus ties, enhancement of SCC of circuit breaker, applications of HVDC-BTB(Back to Back) and FCL(fault current limiter). However, these alternatives have some drawbacks in viewpoints of system stability and cost. As the superconductivity technology has been developed, the HTS-FCL(High Temperature Superconductor-Fault Current Limiter) can be one of the attractive alternatives to solve the fault current problem. Under this background, this paper presents the EMTDC model for resistive type HTS-FCL considering the nonlinear characteristic of final resistance value when quenching Phenomena occur.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.206-208
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• 2002

The transmission system is designed to be protected by 40 kA rate of circuit breaker fer 345 tV system and 31.5 kA and 50 kA rate of circuit breaker for 154 kV system. The short circuit current shows the tendency of exceeding circuit breaker duty for some substations and the tendency will continue if an appropriate countermeasure will not be applied to. In order to solve this problem from the viewpoint of system operation, the 154 kV system is under reconfiguration to be radial systems. This paper presents application effect of resistive and inductive SCFL (Superconducting Fault Current Limiter to Korea power systems. An algorithm of SCFL site decision is suggested.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.216-219
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• 2002

This paper describes the modelling method of the Superconducting Fault Current Limiters (SFCL) for Real-Time Digital Simulator (RTDS). The simulations in this paper were carried out using the R type SFCL. The R type SFCL is developed by using User Defined Component (UDC).