• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.53-54
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• 2017

In this paper, we have studied the electrostatic discharge test for the battery protection circuit module in the lithium ion battery used as a smartphone battery which is used to prevent the explosion hazard due to overcharge, over discharge, and short-circuit. A lithium ion battery of S company was used as an experimental sample, and an ESD gun simulator compliant with IEC 61000-4-2 standard was used for electrostatic discharge injection. The contact discharge was applied to the various pins of the battery protection circuit module in increments of 2 kV in the range of 2 kV to 10 kV and in 5 kV increments in the range of 10 kV to 30 kV.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.7
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• pp.1740-1749
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• 2009

As mobile devices evolve and digital convergence trend is here to stay, mobile phones are built with multiple functions including cameras, MP3s, TVs and game consoles. As a consequence, such multi-functional mobile phones come to spend more power, facilitating development of next-generation ultra-capacity lithium ion battery. In addition, environmental regulations and rising oil prices cause demand for hybrid cars to keep rising. Accordingly, more and more attention is being paid to medium and large batteries and more efforts are being made to realize lower battery prices, higher outputs and stability. This study presented a patent technology related to the lithium ion battery packing that allows reducing processes related, increasing productivity and recycling parts other than the body. The lithium ion battery pack to which protection circuits are elastically attached provides short circuit protection for the circuit and the body and makes electric connection of the circuit and the body easier.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.1
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• pp.47-54
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• 2004

A new high voltage DC power supply is proposed. The proposed power supply is constructed with several power converters connected in series. It is easy to obtain high DC voltage for the same structure of each power converter. The output DC power of the proposed power supply can be disconnected from the load within several hundred microseconds at the instant of a load short-circuit fault. The rising time of the output DC voltage is also as small as several hundred microseconds, and there is no overshoot of the voltage because all of the output filter capacitors keep undischarged state even in load short-circuit condition. Therefore, the proposed scheme is suitable for the protection of frequent output short-circuit and fast on/off switching of output DC voltage. The proposed power supply has improved features such as simple structure, high power factor, and reduced size and volume compared with the conventional schemes. The operating principle is described and the validity of the proposed scheme is proved through simulations and experiments.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.5
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• pp.929-935
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• 2009

As modem industrialized society progresses, the demand for electric power is increasing rapidly. The electric power system is getting amazingly bigger and complicated, which can easily induce serious troubles from the potential of large fault problems and/or system failure. The monitoring and diagnosis of the electric machine for the fault detection and protection has been important part in the electric power system. Most faults in the generator appear in the winding. This paper presents the air-gap magnetic flux characteristic of a small-scale 2-pole synchronous generator according to the faults in the field winding to protect the generator from the fault. The magnetic flux patterns in air-gap of a generator under various fault conditions as well as a normal state are simulated by using finite element method. These results are successfully applied to the detection and diagnosis of the short-circuit condition in rotor windings of a high capacitor generator.

• Journal of Electrical Engineering and Technology
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• v.1 no.4
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• pp.423-426
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• 2006

Distance relays achieve selective tripping by measurement of all short circuit fault conditions inside set reaches. The direction of the fault, forward or reverse is commonly determined with a dedicated measurement to ensure selectivity under all conditions. For the direction decision (measurement) a number of alternatives are available. This paper describes a loop selective direction measurement and illustrates by means of a typical fault why this is superior to a non loop selective direction measurement such as that based on negative sequence quantities.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.36-37
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• 2016

The main cause of electrical fires are caused due to short circuit and open circuit. This is generates an instantaneous electric arc or spark accompanied with such electric faults. These arcs generate a pressed wire, contact badness, and a weakness in the wire coating etc.. This research proposes a protection circuit to prevent open-phase accident due to contact failure of electromagnetic contactor, tracking arc fault, open-phase within the three-phase electrical control panel which is the most commonly applied in the industry. The proposed circuit also alarms and cuts off of power system when electrical faults occurs. In addition, the proposed circuit is validated by various electric accident simulator.

• Fire Science and Engineering
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• v.23 no.3
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• pp.40-47
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• 2009

Nowadays the diversity and large-capacity of electric appliances are strong effect on electrical fires augment in an alarming way. But, as the inactive response characteristics of the existing RCD (Residual Current protective Device) used on low voltage power distribution system, so control of overload and electric short circuit faults, major causes of electrical fires, are not enough. Therefore, this paper is confirmed the unreliability of the existing RCD by electrical fault simulator and is proposed a Electrical Fire Disaster Prevention Device (EFDPD) by using a high precision current sensor (namely, reed switch) for the prevention of electrical disasters in low voltage power distribution system caused by overload or electric short circuit faults. The sensitive reed switch in the proposed EFDPD exactly detects the increased magnetic flux with the overload or the short current caused by a number of electrical faults, and the following, the EFDPD has double protection function which operates self circuit breaker or rapidly cuts off the existing RCD. The proposed EFDPD is confirmed the excellent characteristics in response velocity and accuracy in comparison with the conventional circuit breaker through various operation performance analysis. The proposed EFDPD can also prevent electrical disaster, like as electrical fires, which resulted from the malfunction and inactive response characteristics of the existing RCD.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.140-142
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• 2005

This paper describes the current- based compact digital motor protective relay for low and high voltage induction motors, which are widely used in industrial and commercial power systems. The existing protective relays for motor protection had only overload, short circuit, reverse phase, open circuit and grounding protective elements, and measurement, start/stop control function. But in present day, for automation system, various functions are required, especially motor management and sequence control function and more. To meet these requirements, we developed an economic current-based compact digital motor protective relay which had various function to control, manage and monitor the induction motor.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.264-268
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• 2003

This paper describes a high voltage high power DC power supply which has the ability of pulsed mode operation. The power supply Is constructed with several series connected power converters based on modified multilevel converters. The modified multilevel converters are suitable for the protection of frequent output short-circuit. The output dc power of the proposed converter can be disconnected from the load within several hundred microseconds at the instant of short-circuit fault. The rising time of the dc load voltage is as small as several hundred microseconds, and there is no overshoot of the do voltage because the dc output capacitors keep undischarged state. Analysis, simulations, and experiments are carried out to Investigate the operation and usefulness of the proposed scheme.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.378-381
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• 2002

This paper describes a novel multilevel ad/dc power converter suitable for the protection of frequent output short-circuit. The output dc power of the proposed converter can be disconnected from the load within several hundred microseconds at the instant of short-circuit fault. The rising time of the dc load voltage is as small as several hundred microseconds, and there is no overshoot of the do voltage because the dc output capacitors keep undischarged state. Analysis and simulations are carried out to investigate the operation and usefulness of the proposed scheme.