• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.546-547
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• 2013

This paper proposes an arc fault circuit interrupter (AFCI) using the distorted voltage wave in electric arc faults. It perceives a voltage instantaneously at the time of voltage drop. and occurrence. It is an AFCI of the new concept which operates with high reliability. The primary reason of electric fire is arc and spark. It prevents an electric fire or an electric leakage accident with quick responsiveness. Earth Leakage Circuit Breaker(ELB), Molded_case Circuit Breaker (MCCB) or Residual Current Protective Device(RCD) can not cut off electric arc or spark to be a major factor of electrical fire. This theory will be able to intercept an arc or a spark. which occurrence with periodic. Consequently It raises a reliability and validates a practicality of RCD.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.640-644
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• 1993

A mathematical arc model based on the integral method has been developed to study the arc behaviour of $SF_6$ Puffer circuit breakers during high current period. The interaction between the compression chamber and the arc interrupter plays a critical role in determining the arc behaviour. Computations have been carried out for the puffer circuit breaker of Noeske et al.[1]. The aerodynamic behaviour and electrical characteristics of the puffer circuit breaker have been investigated. In addition, the pressure rise in the compression chamber and arc voltage have been computed and the results compared with the available experimental results of Noeske et al.[1]. Special attention has been paid to the presence of the shock.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3081-3086
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• 2015

Development of a extra-large hydraulic breaker, which could be used for a 100 ton-class excavator were carried out Hot-firing tests were carried out. Before designing a hydraulic breaker, the analysis method to predict the performance such as impact energy and impact rate were studied. Based on the analysis result, the design and manufacture of a extra-large hydraulic breaker were performed, and the breaker were confirmed to operate successfully. The data of impact energy and impact rate were measured during the operation of the breaker, and were compared with the analysis result. The analysis result of impact rate anticipated well the test data, but that of impact energy showed a large difference with the test data. The extra-large hydraulic breaker were successfully developed and the analysis method of impact energy will be updated taking into account friction, hydraulic circuit, etc.

• Progress in Superconductivity and Cryogenics
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• v.19 no.4
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• pp.40-44
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• 2017

This paper analyzed the fault current limiting characteristics of the previously proposed transformer superconducting fault current limiter (TSFCL) interruption system according to its transformer type. The TSFCL interruption system is an interruption technology that combines a TSFCL, which uses a transformer and a superconductor, and a mechanical DC circuit breaker. This technology first limits the fault current using the inductance of the transformer winding and the quench characteristics of the superconductor. The limited fault current is then interrupted by a mechanical DC circuit breaker. The magnitude of the limited fault current can be controlled by the quench resistance of the superconductor in the TSFCL and the turns ratio of the transformer. When the fault current is controlled using a superconductor, additional costs are incurred due to the cooling vessel and the length of the superconductor. When the fault current is controlled using step-up and step-down transformers, however, it is possible to control the fault current more economically than using the superconductor. The TSFCL interruption system was designed using PSCAD/EMTDC-based analysis software, and the fault current limiting characteristics according to the type of the transformer were analyzed. The turns ratios of the step-up and step-down transformers were set to 1:2 and 2:1. The results were compared with those of a transformer with a 1:1 turns ratio.

• Journal of the Korean Society of Safety
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• v.30 no.3
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• pp.26-31
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• 2015

This paper describes the characteristics of voltage drop and thermal for poor connection on electrical connector of circuit breaker in control box of small size pulverizer. In order monitor, we did the changes of RMS in voltage and temperature value with video and made normal state over $2.5N{\cdot}m$ and poor connections state below $0.2N{\cdot}m$ by screw gage. In case of voltage signal, the voltage drop was increased when the current was increased due to poor connections. In case of temperature signal, the temperature difference indicates ten times at 5A and fourteen times at 15A in the normal state. According to increase thermal energy, the insulation of electrical wiring and connector of circuit breaker can be carbonized. The results of this study will be useful to the development of preventive devices and system for electric fire by poor connection at small size pulverizer.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.5
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• pp.578-585
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• 2007

A vacuum circuit breaker (VCB) with permanent magnet actuator (PMA) has been studied in this study. Electromagnetic field analysis and dynamic simulations have been carried out for optimal design of VCB by using commercial software Maxwell and ADAMS. This simulation model can be an effective method for the VCB, which has non-linear output force of PMA, friction, and impact for operations. An experiment has been conducted to evaluate correctness of the simulated model. By using this evaluated model, the displacement and velocity characteristics of the VCB have been simulated with following conditions : (1) The different output forces of PMA have been applied, (2) The friction conditions in follow lever shaft and moving part have been changed, (3) The mass conditions of moving part have been changed. The simulated results shows that the velocity characteristics are mainly determined by the output force of PMA. The effects due to the changes of friction conditions against the dynamic characteristics was small, and the mass conditions of the moving parts affect the velocity and a bouncing phenomenon of VCB. From these results, the optimal design conditions for the VCB have been derived.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.3
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• pp.526-531
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• 2016

This paper presents an experimental study on the optimal settings for the selected DC fault relay (50F) to improve the operating performance for the high-speed circuit breaker on DC feeding system which ensure safety within rolling stock maintenance depot. In this study, current supplied to overhead contact wire was calculated on 1 ms interval to analyze the correction values of DC fault selective relay for the operation of current supply cutout. Particularly, standards for the accurate detection of accidents between an electric railway vehicle and the electric power facilities are shown by investigating the optimal correction values for detection of fault current, and the results indicated that it takes about 213 ms for the DC fault selective relay(50F) to fully open. In the future, the correction values of DC fault selective relay suggested in this paper will be used as the reference values of protective relay for the safe operation of DC electric railroad system such as urban railway.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.3
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• pp.357-364
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• 2015

The power system configuration is changed to solve increasing power demand. This changes in power system configuration with mesh-, network grid generate the problem of fault current increase. Superconducting fault current limiter (SFCL) has been expected the one of the solutions to solve this problem. And there has already been reported much to the application and research of SFCL in the power distribution system. However, the application and research of SFCL are insufficient in a transmission power system. Also, the fault current limiting effect by the SFCL varies with installation location of SFCL. Therefore, this paper constructed the power transmission system through experiment and analyzed installation location method of SFCL using the current rate of each circuit breaker (CB) according to fault location.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.170-172
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• 1998

In the future, it is expected that a fault-current of 345kV power system is beyond 60kA and stability and reliability in transmission system will be more important. From these points of view, we needed a development of a circuit breaker having ability of breaking a large fault current, more than 60kA. This paper describe the specification and history of a development on 362kV 63kA 8000A GCB(Gas insulated Circuit Breaker) of which we completed a development. A development of this GCB will contribute to improve the technique to design and make GCB, and the stability and reliability of power system in our country.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1840-1842
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• 2003

This paper describes an experiment of detecting a temperature and components of arc plasma of electrical circuit breaker with a spectroscopic system. The system includes an optical fiber, a monochromator which has three gratings from low to high resolution and ICCD of which time resolution is 50 ns. This system enables measuring a temperature and components of arc plasma of a circuit breaker which is generated and extinguished in a few ms. We use a Planck's law and Boltzmann Plot method for calculating a temperature of arc plasma. A Xenon lamp is used for calibrating the system and this is very important for calculating a temperature of arc plasma. In this study, Arc plasma of Ag and Cu contact was investigated and these represent the contact of low voltage and extra-ultra high voltage circuit breaker, respectively. 8 $kA_{rms}$ test current was applied with a capacitor bank.