• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.1
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• pp.56-61
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• 2009

In this paper, A telemetering control system for the HDTV SMPS Aging System is developed. Manual Aging System is usually used to measurement of a produced SMPS. But in this system, the respective operator is arranged and monitoring the test cycle visually- According to an excess of the test time and mistakes of an operator, the reliability makes come to be low. Therefore as using the telemetering control system, it improves a productivity and a reliability of the HDTV SMPS. In the developed system, elec1rical signal is measured from aging system, and converted into the digital signal. Also the telemetering control system is composed of many units - telemetering control units for collecting the data, data relay units for the digital transmission service, data division for the multichannel realization.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.435-438
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• 2004

Lately, the Intelligent Electronic Device(ED) and the Power System Automation make subjects of discussions and studies. The IED uses microprocessors to practice a lot of functions. In the analog time, an equipment practices only one or two functions. But according to the development of microprocessor and digital technology, it can be implemented by using those kinds of state of the art technology and its function is become more and more powerful. Also, the proliferation of IED makes possible to construct power system automation. An automation of power system make more convenient, safe, and accurate power system. In this paper, a digital protective relay which is a kind of IED and the power automation system are briefly discussed with development and application cases.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.440-442
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• 2000

This paper describes the digital distance algorithm in case of combined transmission line connected with overhead line and underground cable. Actually as fault is occurred in cable, it results in the complicated phenomena due to the several kind of grounding method in the sheath of cable. Accordingly the impedance. Therefore the correct impedance calculation algorithm is requested in combined transmission line to avoid the wrong trip of relay. This paper presents the development result of impedance calculation algorithm In such transmission line.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.316-318
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• 2005

This paper presents the development of the training courses using real time digital simulator (RTDS). This training courses for the engineers who are working at power system field are expected to be developed the sixteen courses. We describe the developed five courses in this paper which are protective relay testing, voltage compensation using a voltage compensator such as SVC and capacitor, the restoration of power for KEPCO system, phase unbalance simulation of transmission lines and harmonic analysis. We also describe the benchmark system composed of six buses with three machines for the KEPCO system to verify the power system analysis.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.262-264
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• 2005

최근 IT산업의 급격한 부상으로 전력산업에서도 운영시스템이나 설비들이 통합되거나 소형화 및 다양한 가능을 보유하는 둥 많은 변화가 진행되고 있다. 전국의 많은 154kV 배전변전소에는 기존의 유도원판형 보호계전기가 점차 철거되고 기계적인 동작시간차를 고려하지 않아도 되는 디지털보호계전기로 교체되어 있는 중이다. 따라서 배전선로 보호협조 운영기준은 유도원판형 보호계전기만을 고려하여 제정되어 있기 때문에 합리적인 배전계통운영을 위하여 보호협조 운영기준은 현실에 알맞도록 개선되어야 할 것이다. 이 논문에서는 배전 변전소에서 사용중인 디지털보호계전기를 소개하고, 도입에 따른 배전선로 보호협조 방안을 제시하고자 한다.

• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.55-58
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• 1992

Due to the fault signal containing high and/or slowly decaying dc off-set component, saturation of current transformers cause errors in reproducing secondary current and therefore, secondary current is distorted, which cause relay to maloperate. In this paper, a new method which determines whether current transfomer is saturated is proposed. By designing digital filter of current transfomer, although secondary is distorted, exact secondary current can be reproduced.

• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.63-66
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• 1992

This paper presents the real time digital differential protection scheme for transformer. Inrush and Internal fault conditions are distinguished by the relative magnitudes of fundamental and second harmonic components which are extracted from differential currents. The algorithm is simulated and implemented using a prototype relay which is made up of Intel 80286 CPU and Motorola DSP-56001. The testing data of inrush and Internal fault signals which are sampled at a rate of 12 times a cycle are obtained by EMTP, and tested In real time using simulator which downloaded those data.

• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.59-62
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• 1992

Power system fault transient signals are highly distorted due to the presence of high frequency components in the voltage and current signals and an exponentially decaying dc-offset component in the current signals. Modern protective relays have to make reliable fast decisions about the nature of a fault in the presence of such transients. To use a dc-offset removing filter makes relay algorithms much fast and reliable for detecting a fault. In this paper, several dc-offset removing filters are described, and characteristics of them are compared.

• ETRI Journal
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• v.31 no.4
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• pp.357-364
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• 2009

In this paper, we propose a novel equalization on-channel repeater (OCR) with a feedback interference canceller (FIC) to relay terrestrial digital multimedia broadcasting signals in single frequency networks. The proposed OCR not only has high output power by cancelling the feedback signals caused by insufficient antenna isolation through the FIC, but also shows better output signal quality than the conventional OCR by removing multipath signals existing between the main transmitter and the OCR through an equalizer. In addition, computer simulations and laboratory test results demonstrate that the proposed OCR successfully cancels feedback signals and compensates channel distortions and provides a higher quality transmitting signal with higher output power than conventional OCRs.

• Journal of Information Processing Systems
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• v.14 no.5
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• pp.1272-1285
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• 2018

The paper presents a novel embedded multifunctional media sever (EMMS) for mobile devices to receive various media programs. Being different from other contemporary system research, the paper mainly studies how to design a reception solution for terrestrial digital television (DTV) on mobile devices and how to enable mobile devices can receive DTV program, enjoy video-on-demand (VOD), achieve video surveillance and relay Internet video program via local Wi-Fi simultaneously. In the system design, we integrate broadcasting-terrestrial DTV tuner, streaming media re-transmission system, VOD disk, video camera and access interface to the Internet into EMMS, which can either receive terrestrial DTV radio signals and demodulate out digital transport stream (TS), or can read streaming media bit-stream from VOD disk, surveillance camera or access interface to the Internet. The experimental results show the proposed system is stable and quality-efficient. Comparing with the other systems, the proposed system has the least packet loss rate and response time.