• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.4
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• pp.321-327
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• 2006

In this paper, An Automatic Synchronous Switch Post Regulator for Multi-Output Flyback Converter is proposed. The proposed circuit is composed simply using a new automatic synchronous switch instead of conventional complex Switch Post Regulator owing to difficulty of drive circuit materialization and synchronization between main output and auxiliary output. By using the proposed circuit, we can make simple and inexpensive Multi-Output Converter with variable and accurate output voltage and proved adequacy of proposed circuit through experiment, simulation and theoretical analysis.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.4
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• pp.467-473
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• 2013

The addition of disconnect switches to a distribution feeder or the replacement of the manual switches with the automatic switches do, in general, increase reliability by decreasing the duration of the outage of many to the customers on the feeder and reducing the outage section. However, the improvement of reliability in power distribution system causes an increase of the investment cost, for example, replacement costs, labor costs, and so on. For this reason - the balance between investment and reliability improvement - many studies about the appropriate level of investment have been conducted. In this paper, we suggest the algorithm for determining the reasonable switch automation rate in the power distribution system. We evaluate the customer interruption cost and reliability for several cases - these cases relate with the switch automation rate - in the domestic metropolitan power distribution system, estimate the effectiveness of changing the manual switch to automatic switch quantitatively. These results can help the determining on the disconnect switch's automation rate.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1978-1979
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• 2007

In this paper, the authors introduce a high-speed microprocessor based on automatic vacuum capacitor switch with a modified digital filter design using distributed arithmetic. The automation trends particularly the automatic vacuum capacitor switch has helped ameliorate the power factor essentials and automatically triggered to close when the line current exceeds rated value. Microprocessor relays use digital filters to extract only the fundamental and attenuate harmonics. To provide optimum speed characteristics a distributed arithmetic based filter design in the microprocessor controller which not only enhances filtering speed but additionally enables lower power consumption at the cost of area has been introduced. The result is a unified description that describes a digital filter structure down to bit level.

• JOURNAL OF ELECTRICAL WORLD
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• no.10 s.106
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• pp.22-27
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• 1985

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.794-797
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• 2005

The automatic load transfer switch (ALTS), a kind of electric power switch, typically automatically transfers electrical loads from a normal electrical power source to an emergency electrical power source upon reduction or loss of normal power source voltage. It can also automatically re-transfer the load to the normal power source when the normal voltage has been restored within acceptable limits. The transfer operation of ALTS is accomplished by a spring-driven linkage mechanism. In order to control or delay the transfer switching time, the ALTS studied in this paper uses the superposed leaf springs, which are subjected to impact leadings in contacting with electrical contacts. Therefore, to confirm whether the springs has enough mechanical endurance in ALTS, we build a finite element model of the superposed lear springs using LS-DYNA and perform the impact and fatigue analysis.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.4
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• pp.297-302
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• 2015

Replacing a manual switch installed in a feeder for a distribution system with an automatic one increases the reliability of the electric power system. This is because the automatic switch can shorten the duration of a fault the customer experiences by splitting the faulty section faster than the manual one does. However, improving the reliability of the distribution system may increase investment costs. Here, the investment costs include automatic switch cost, replacement work cost and labor cost. For this reason, importance should be attached to the proper balance between the increase of the investment costs and the improvement of the reliability of the distribution system. This article analyzed reliability index and economics when manual switches installed in a feeder (RBTS Bus2 model) was replaced by automatic ones. In addition, it attempted to draw the optimum rate of automation of manual switches by automatic ones using the GRG optimization method, considering the current economic requirements.

• JOURNAL OF ELECTRICAL WORLD
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• s.403
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• pp.73-73
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• 2010

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1530-1535
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• 2003

The automatic load transfer switch (ALTS) typically automatically transfers electrical loads from a normal electrical power source to an emergency electrical power source upon reduction or loss of normal power source voltage. It can also automatically re-transfer the load to the normal power source when the normal voltage has been restored within acceptable limits. The transfer operation of ALTS is accomplished by a spring-driven linkage mechanism. In this paper we build a dynamic model of driving mechanism for ALTS using ADAMS and checked the characteristics of the transfer operation. Finally we performed a detailed design of the driving mechanism through results of analysis and confirmed it to satisfy design requirements.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.12
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• pp.2125-2130
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• 2010

The neutral section on electric railway system is significant sector in order to prevent short circuit of two electric powers. However, while electric trains pass the neutral section, those speed is decreased and the accident of AC electric traction system and the electric train would be occurred. So the countermeasures are urgently needed. The automatic power switching technology system that is current being research and development is system to improve these problems. Because main object of this system is power change using static switch in the neutral section, it's expected to cause a variety of transients. Especially, onboard transformer inrush current for electric railway train can be occurred more than rated current according to switching time. Therefore, the analysis and improvement are needed to ensure the stability of this system. In this paper, we analyze the operating characteristics of the automatic power switching technology system. Especially, it reviews inrush current according to the closing phase angle. And we propose control plan of inrush current considering the case that voltage is maintained due to counter electromotive force and regenerative braking operation of electric railway train. Finally, the proposed control scheme was reviewed using the transient analysis program.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2883-2885
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• 2000

ATS(Automatic Transfer Switch), the secondary power supply system prepared for' temporary power fail on main in KEPCO in industrial field or running a important system. is developed. In this development, we prove that the proposed system is safe with results in a few environment testing focused on a solution against a poor environment by making virtual environment for a solution on problems of system reliability to switch more safely.