• Journal of Biosystems Engineering
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• v.22 no.3
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• pp.303-310
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• 1997

Motivated by the need fir developing the new method of weed control in place of chemical weedicide, this paper aims at making good use of electricity against environmental pollution. Compared with chemical weedicide, the electric method of weed control is functionally more versatile, effectively more rapid, and lower in terms of cost. In particular, this method will contribute to environmental protection. In detail the electrical weed control system which is the simple circuit for generating the electric current of high voltage is comprised of step-up transformer which rectifies the current and the capacitor which stores the energy. The effectiveness of electrical weed control system is evaluated by germination rate and control of Dgitaria Sangvinalis(Galinsoga ciliate). As a result, the electrical weed control system(high voltage spark discharge) can kill weeds effectively

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.3
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• pp.472-480
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• 2007

This paper analyzes overvoltage on testing line for various parameter effect examination. Model systems consist of overhead line and underground cable. The model considered actual characteristic data of distribution lines. and will be constructed at testing yard. The simulations were performed under various line configuration such as cable kinds, cable length, lightning wave, lightning wave time, transformer and branch circuits. The simulation models are established by EMTP/ATPDraw and Line Constants are calculated by ATP_LCC. When lightning surge strikes on conductor of overhead line, EMTP/ATPDraw calculates overvoltage in many cases. Simulation results will be compared with real testing results at testing yard. The compared results will be used to establish protection methods in actual underground distribution systems.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.293-295
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• 2008

초전도 한류기의 용량증대를 위해서는 초전도 소자의 직 병렬 연결이 필요하다. 저항형 초전도 한류기는 초전도 소자의 불균형 퀜치로 인해 초전도 소자의 전력분담이 불안정하다. 변압기형 초전도 한류기는 2차측 코일과 초전도 소자 2개를 중성선을 이용하여 직 병렬로 연결하였다. 중선선 연결을 통해 사고전류에 따른 초전도 소자의 퀜치 특성이 개선되었다. 초전도 소자의 동시 ��치는 전력 부담을 각 소자에 동일하게 부담시킴으로서 한 소자에 편중되는 것을 방지한다. 또한 전압분배도 동일하게 할 수 있게 된다. 결론적으로 변압기형 초전도 한류기의 용량증대를 위해서는 2차측 코일과 초전도 소자 사이에 중선선 연결을 함으로써 그 답을 얻을 수 있다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.325-330
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• 2005

Recently an increase of sensor and power trandusers in control equipment system has caused many kinds of noise. These kinds of noise came out the mis-operation equipment and demage program memories of control circuits. In this paper, the noise generation of control equipment system han been measured and analyzed. Additionally, the effective protection equipments to reduce noise like as Noise Cut Transformer, Equipotential Bonding, Power Noise Rejector, Noise Filter has been applied and proposed the measured results.

• Proceedings of the KIEE Conference
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• 2004.10a
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• pp.143-146
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• 2004

This is a thesis that 100W class open frame type power module of a quarter-brick size appropriate for telecommunication is reported. The input voltage is established between 36 and 75 in range in order for power module to be utilized for the telecommunication, and output were set at 3.3V and 30A. A number of parts used for transformer, inductor, and hit sink are composed of PCB in order for DC-DC converter to be lowered below 8 mm. A constant current control circuit was annexed to the system as well as basic protection prototypes such as over-voltage, over-current, and over-temperature were well considered to enhance more credibility, and were tested. As a result, high circuit performance and credibility turned out to be significant.

• Proceedings of the KIPE Conference
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• 2007.11a
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• pp.43-46
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• 2007

In this paper, a novel new pulse power generator based on IGBT stacks is proposed for pulse power application. Proposed scheme consists of series connected 9 power stages to generate maximum 60kV output pulse and one series resonant power inverter to charge DC capacitor voltage. Each power stages are configured as 8 series connected power cells and each power cell generates up to 850VDC pulse. Finally pulse output voltage is applied using total 72 series connected IGBTs. The synchronization of gating signal is important for series operation of IGBTs. For gating signal synchronization, full bridge inverter and pulse transformer generates on-off signals of IGBT gating and specially designed gate power circuit was used. Proposed scheme has lots of advantages such as long lifecyle, compact size, flat topped pulse forming, small weight, protection for arc, high efficiency and flexibility to generate various kinds of pulse output.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.710-713
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• 1992

An AVR for OLTC controls motor tap in transformer in order to supply constant power source. Recently for society which is higher informative and more automatic, in our research, the digital AVR for OLTC is developed that can perform more functions and higher functions ( mesurement, display, protection, control ) using microprocessor in a different control method than the conventional AVR. The experiment result is also present.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.713-717
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• 2004

This is a thesis that a quarter-brick size of 100W class open-frame type on board power module comprising telecommunication application is reported. The input voltage is established between 36 and 75 in range in order for power module to be utilized for the telecommunication application, and output were set at 3.3V and 30A. A number of parts used for transformer, inductor, and hit sink are composed of PCB in order for DC-DC converter to be lowered below 8 mm. A constant current control circuit was annexed to the system as well as basic protection prototypes such as over-voltage, over-current, and over-temperature were well considered to enhance more credibility, and were tested. As a result, high circuit performance and credibility turned out to be significant.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.5-7
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• 2006

Current transformers(CTs) whose rating is selected per a full load current of a feeder in high voltage system can be easily saturated due to high fault current that may be several hundred times of the full load current of the feeder. However, the protective relay shall operate properly at the fault without mis-operation under the CT saturation. So, in selecting the CT rating, it is necessary to consider the behaviour of CT and a performance of protection scheme in condition where CT can be saturated. In this paper, a performance of CT and a degree of saturation are studied and verified whether its ratings are proper for the operation of the protective relay.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.444-446
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• 2005

This paper describes a current differential relaying algorithm for power transformers with an advanced compensation algorithm for the secondary current of CTs. The comparative study was conducted with and without the compensating algorithm. The algorithm can reduce the operating time of the relay in the case of an internal fault and improve security for external faults. The performance of the proposed algorithm was investigated when the C100 CT, a quarter of the rated CT(C400), is used.