• Progress in Superconductivity and Cryogenics
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• v.5 no.1
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• pp.103-106
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• 2003

The short circuit current problem is one of the operational problems that need to be solved by power system engineers in Korea. It is an important issue in the Seoul metropolitan area especially because of highly meshed configuration. Currently, it is regulated by changing 154 kV system configuration from loop connection to radial system, by splitting of the bus where load balance can be achieved, and by upgrading circuit breaker rating. A development project for 154 kV/2 KA SFCL application to 154 kV transmission system after 2010 is proceeding. In this paper, a feasibility study of superconducting fault current limiter (SFCL) is carried out in Seoul metropolitan area to find out the effects of its application and feasibility. This study shows that it can reduce fault current considerably, and as it can minimize the upgrading of circuit breaker rating, the economic potential of SFCL is evaluated positively.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.320-321
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• 2011

As the scale of industries expands, the facilities of the industrial customer become larger and more complex. When a fault occurs in the system, the circuit breakers play an important role in minimizing causalitites by quickly tripping the faulted line. Since the capacity of the receiving-end has increased in size, an examination is needed to be performed between the industrial customers and the conventional circuit breakers. The transient recovery voltage, which is the initial transient characteristics of the voltage across the breaker when tripped, is an important factor in determining the circuit breaker's performance. In this paper, a TRV analysis on the large-scale industrial customer is being performed utilizing PSCAD/EMTDC.

• Progress in Superconductivity and Cryogenics
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• v.5 no.2
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• pp.1-7
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• 2003

Nowadays, one of the serious problems in KEPCO(Korea Electric Power Co-Operation) system is the more higher 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(High Voltage Direct Current-Back to Back) and FCL(fault current limiter). But, 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(Electro-Magnetic Transient Direct Current) model for resistance type HTS-FCL considering the nonlinear characteristic of final resistance value when quenching phenomena occur.

• 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 Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.03b
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• pp.28-28
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• 2010

The higher the short circuit currents, the faster the interruption takes place. For increasing the interrupting performance of the MCCB, it is important to design optimally the adjustable tripping device, the open /shut mechanism, and the arc quenching room in the MCCB. This paper is focused on understanding the interrupting performance, more specifically of the grid and the fix contact, based on the shape of the arc quenching room in the current MCCB.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.524-526
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• 1997

High speed DC circuit breakers (HSCB) are indispensable for protection of DC electric subway substations from fault current. However, the HSCB has mechanical contact to wear, which requires rather frequent maintenance, we have succeeded in developing and manufacturing a GTO DC circuit breaker using GTOs and ZnO varistors. In this paper, we describes the outline of the system itself, its characteristics and test data.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.3
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• pp.107-115
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• 2002

This parer presents the analysis of hot gas flow in puffer-type circuit breakers using FVFLIC method. For the analysis of arc-flow interaction, the flow field is analyzed from the equations of conservation for mass, momentum and energy with the assumption of local thermodynamic equilibrium state. The arc is represented as the energy source term composed of ohmic heating and radiation term in the energy conservation equation. Ohmic heating is computed by the electric field analysis only within the conducting plasma region. An approximate radiation transport model is employed for the evaluation of emission and absorption of the radiation. The analysis method was applied to the real circuit breaker model and simulation results such as pressure rise and arc voltage were compared with the experimental ones.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.3B no.2
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• pp.74-78
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• 2003

This paper describes the operating characteristic analysis of the PM-type linear oscillatory actuator used as a magnetic circuit breaker for the electromagnetic field, electric circuit, and mechanical motion problems. Transient calculations are based upon a 2D finite element magnetic field solution including non-linearity of materials. Changes of the dynamic characteristics from the eddy current in the plunger are quantified from finite element analysis. A new laminated model is proposed to decrease the eddy current effect.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.12
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• pp.661-669
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• 2004

As the load density of KEPCO system is higher, the fault current can be much higher than SCC(Short Circuit Capacity) of circuit breaker. Fault current exceeding the rating of circuit breaker is a very serious problem in high density load area, which can threaten the stability of whole power system. Even though there are several alternatives to reduce fault current, as the superconductivity technology has been developed, the HTS-FCL (High Temperature Superconductivity Fault Current Limiter) can be one of the attractive alternatives to solve the fault current problem. This study presents the application plication of 154kV HTS-FCL in Korean power system.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.11
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• pp.527-532
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• 2005

During the last ten years the new interruption techniques, which use the arc energy itself to increase the pressure inside a chamber by the PTFE nozzle ablation, have displaced the puffer circuit breakers due to reduced driving forces and better maintainability. In this paper, we have investigated the thermal flow characteristics inside a thermal puffer type gas circuit breaker by solving the Wavier-Stokes equations coupled with Maxwell's equations for considering all instabilities effects such as turbulence and Lorentz forces by transient arc plasmas. These relative inexpensive computer simulations might help the engineer research and design the new interrupter in order to downscale and uprating the GIS integral.