• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.5
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• pp.60-67
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• 2003

The goal of this paper is to improve EMC performance of circuit breaker. Circuit breaker and control cubicle are interconnected by multi control cable. Also many control cables are laid on each apparatus. These control cables are directly connected by electronic components. So control cables are very important to improve EMC performance of circuit breaker. This paper suggests installing a ground conductor in parallel(PGC) to control cables. Also this paper suggests using shielding cables as secondary cables of voltage transformer in circuit breakers, and grounding both ends of shielding. After applying suggested methods, we verified EMC performance of circuit breaker is improved.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.666-667
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• 2010

• Journal of Electrical Engineering and Technology
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• v.7 no.5
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• pp.778-783
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• 2012

The synthetic short-circuit making test to adequately stress the circuit breaker has been specified as the mandatory test duty in the IEC 62271-100. The purpose of this test is to give the maximum pre-arcing energy during making operation. And this requires the making operation with symmetrical short-circuit current that is established when the breakdown between contact gap occurs near the crest of the applied voltage. Also, if the interrupting chamber of circuit breakers is designed as the type of common enclosure or the operation is made by the gang operated mechanism that three-phase contacts are operated by one common mechanism, three-phase synthetic making test is basically required. Therefore, several testing laboratories have developed and proposed their own test circuits to properly evaluate the breaker performance. With these technical backgrounds, we have developed the new alternative three-phase making circuit.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.1
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• pp.12-18
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• 2014

This paper analyzes how to calculate the three phase short circuit current calculation procedures used in the IEC 60909 short circuit. It presented the new procedure of the fault current for the interrupting capacity of the circuit breaker. This procedure is applied to the future power system and calculates the fault current. Power demands are increased because of the growth of the economy for this reason, the fault current of the power system is largely increased and the fault current procedure for the proper interrupting capacity calculation of the existing or the new circuit breaker is essential. How to calculate the three phase short circuit current for ac electrical system and select the high voltage and low voltage circuit breaker based on IEC 60909 standards.

• Journal of Magnetics
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• v.21 no.3
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• pp.340-347
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• 2016

At the stroke end of an electromagnetic circuit breaker, the high speed of the mover makes a huge impact at the contact point, which induces the rebound problem of the mover that causes a breaker failure. Thus, a speed reduction equipment is required to address such problems. This study suggests to use an electric brake reduces the speed at the end of the stroke. The proposed circuit breaker which adopts the electric brake has a variable speed reduction function such that the continued rebound phenomenon ceases to occur. The electric brake is designed by the Finite Element Method (FEM) and the circuit and motion equations are solved using Time Difference Method (TDM). The comparisons between the simulation and experiments demonstrated the usefulness and validity of this study.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.695-698
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• 2008

Self-blast circuit breakers utilize the energy dissipated by the arc itself to create the required conditions for arc quenching during the current zero. During the arcing period, high pressure, temperature and radiation of the arc could burn in pure SF6 gas and PTFE nozzle. Ablated nozzle shape and $SF_6$-PTFE mixture vapor affect the performance of an self-blast circuit breaker. After a number of tests, nozzle in circuit breaker is disassembled, a section of ablated nozzle is investigated precisely. Using computational fluid dynamics, the conservation equation for the gas and temperature, velocity and electric fields within breaker is solved. Before applying a section model, developed program is verified with experimental data. Performance of ablated nozzle shape is compared with original model through analysis program.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.688-692
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• 2000

This study proposed design parameters of opening spring of circuit breaker that cut off the over-current in order to protect the electric device about opening speed using the energy method. We simulated the opening kinetic energy, the potential energy of opening spring and the design parameters of opening spring with respect to opening speed of VCB (Vacuum Circuit Breaker)'s moving contactor which has 24kV 25kA break capacity. From the result of simulation the initial tensional force and the final tensional force of the opening spring chose 107kgf and 282kgf respectively. Through the dynamic analysis using ADAMS, We verified that the opening speed of moving contactor satisfied break capacity of VCB and analyzed opening dynamic characteristics of VCB such as the opening displacement, the opening velocity and the opening acceleration of moving contactor in time domain.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.4
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• pp.233-239
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• 2000

There are many difficult problems in analyzing the gas flow in puffer type circuit breaker such as complex geometry, moving boundary, shock wave and so on. To predict the interruption performance accurately, these should be considered in the simulation. In this paper, the analysis procedure of the cold gas flow in the circuit breaker is presented. Euler equation is solved by FVFLIC method which is an explicit time difference scheme for an unsteady flow computation. Moving boundaries are treated with a cell elimination-addition technique. The pressure and density in front of piston are calculated from the rate of the cell volume change. The presented method is applied to the real circuit breaker model and the pressure in front of the piston is good agreement with the experimental one.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.68 no.1
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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.

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.6
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• pp.495-499
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• 2012

Recently, DC distribution systems become hot issues since DC type loads increase rapidly according to the expansion of IT equipment such as computers, servers, and digital devices; DC type loads will cover 50% for all electricity loads in 2020 which was mere 10% in 2000. DC distribution systems are also accelerated by the expansion of renewable power systems since they are easy to be interfaced with DC grids rather than AC grids. However, removing the fault current in DC grids is comparably difficult since the current in DC grids has non zero-crossing point like in AC grids. Thus, developing dedicated DC circuit breakers for DC grids is necessary to get safety for human and electrical facilities. Magnet arc extinguishing method is proper to small size DC circuit breakers. However, simple Magnet arc extinguishing method is not enough to break inductive fault currents. This paper proposed a novel DC circuit breaker against inductive fault current defined by IEEE C37.14-2004 Standard for Low-Voltage DC Power Circuit Breakers Used in Enclosures. The performance of the proposed DC circuit breaker was verified by an experimental circuit breaker test system built in this research.