• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.155_156
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• 2009

대학교 및 교육시설의 전력시스템을 담당하는 변전소는 공급의 신뢰도 및 안정성이 중요하다. 그러므로 보호시스템의 확실한 동작 확보를 위한 각종계전기의 원할 한 보존 상태와 전력품질에 저해되는 각종요소에 대한 방지대책이 필요하다. 특히 중요 실험실은 무 정전 전력공급에 의한 집중관리를 필요로 하며 변전설비의 정상적인 동작확보를 위한 노력도 필요하다. 먼저 급전방식의 특성과 설비의 특징을 살펴보고 보호계전기의 확실한 동작을 위한 다중접지계통(22.9kv)방식과 비 접지계통(6.6kv)방식의 보호계전방식에 관하여 검토해 보았다. 그리고 각 요소별 고장률을 산정하고 전력품질의 저해요소와 신뢰도 향상방안에 관하여 살펴보았다. 이를 통해 전력시스템의 안전한 사용과 고품질의 전력을 공급할 수 있을 것으로 판단된다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.671-672
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• 2007

국내 배전선로는 다중으로 중성선을 접지하여 운영하고 있어 지락고장이 발생하면 큰 고장전류가 발생하며, 이는 중성선 및 가공 지선과 접지극으로 분류되어 전원측으로 귀로한다. 유도전력기술기준에서는 이 분류율을 배전선로의 경우 50%로 규정하고 있어 배전선로 신 증설시 통신선과의 이격거리 확보에 어려움이 발생하고 있다. 따라서 본 논문에서는 국내 배전선로의 1선 지락전류의 분류율을 기술적으로 검토하기 위해 배전선로 설계기준을 바탕으로 1선 지락고장전류의 대지유입률을 모의하고 그 결과를 분석하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.6
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• pp.660-669
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• 2010

In this paper, a multiple antenna system for next generation mobile applications is proposed. The proposed MIMO antenna consists of two parallel folded monopole antennas with the length of 100 mm and spacing of 6 mm and a decoupling network which locates at the top side of a mobile handset. In order to improve the isolation characteristic at the LTE band 13, a decoupling network was added between the two antenna elements placed close to each other. The decoupling network, consisting of two transmission lines, a shunt reactive component and common ground line, is simple and compact. To obtain the wide bandwidth characteristic, an wide folded patch structure generating the strong coupling between feeding and shorting lines through the slit is used at the bottom side of a mobile handset. Also, the performance of a multiple antenna system composed of three antenna elements is analyzed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.1
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• pp.90-97
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• 2010

In this paper, we propose antenna topology and ground plane shape to improve the performance of PIFA (Planar Inverted F Antenna) which is built-in mobile phone. First, we designed the PIFA antenna consists of multiple radiators to provide multi-current paths. Then we designed U-shaped ground plane on the PCB under the antenna. The proposed antenna structure shows TRP/TIS improvement of 2.0 dB/3.7 dB for GSM and 2.2 dB/ 2.0 dB for DCS and 0.8 dB/1.5 dB for PCS and 1.3 dB/0.7 dB for WCDMA at the free space.

• The Journal of the Acoustical Society of Korea
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• v.31 no.5
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• pp.309-316
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• 2012

This paper suggest configuration method of small-size system and design method of module using multi power. In particular module designed to focus on PDN(Power Distribution Network) and filter configuration method to improve the characteristics of noise sensitive analog IC. For the prevention of high-voltage noise, manufactured module is used the ground-isolated technique and via stitching, and is connected grounds with a series of filters. In this paper, so we analyzed PDN structure through the simulation using lumped modeling and confirmed through measurement. Simulation results, when connecting 4.7uH inductor, we made certain that noise of -7dB decreases much more than when it did not. And it was confirmed 12% less than Background Noise.

• 전기의세계
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• v.20 no.1
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• pp.41-44
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• 1971

현재 한국전력에서 시설하고 있는 22.9KVY 다중접지배전방식은 전력수송면에서는 가장 경제적방식으로서 각광을 받고 있으나 인접한 통신선에 미치는 유도장해는 타의 비접지방식보다 문제가 됨으로 이에 대한 해결방안이 수립돼야 한다. 본 보고는 이러한 유도장해 감소 대책연구의 일부로서 전력측(한전)과 통신부서(체신부, 철도청, 내무부, 국방부)의 합동으로 건설한 경기 오산지구의 22.9KVY 모의 배전계통에서 지난 5월에 실시한 1선지락고장시의 전자유도전압 합동측정치의 분석보고이다.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3126-3128
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• 1999

In 22.9kV-Y overhead lines, if there is an earth fault, high fault current causes surge type over-voltages around this place. There are generally two types of earth faults. One is an earth fault which occurs when a voltage line falls to earth line. The other occurs when a voltage line directly falls to the earth. This study presents an analysis method on the earth fault.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.10
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• pp.817-820
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• 2018

In this letter, a compact multiple-input multiple-output(MIMO) antenna design for a 2.4 GHz wireless local area network(WLAN) band is proposed for use in smart glasses. To miniaturize the MIMO antenna system, a ground plane is employed within the antenna and a T-shaped ground is proposed. To achieve wideband isolation, dual resonance is formed by the ground mode. One resonance is created by the T-shaped ground and the second resonance is created by adding a slot and a capacitor between the two feed lines. The measurements show that the reflection coefficient characteristic was less than -5.1 dB, whereas the isolation obtained was less than -20 dB. The diversity performance was evaluated using the measured two-dimensional radiation patterns, and the envelope correlation coefficient(ECC) values achieved in the target band(2.4~2.5 GHz) were less than 0.1.

• Journal of Advanced Navigation Technology
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• v.14 no.3
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• pp.391-396
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• 2010

This paper presents some important research result comparisons for multi function RF modules which use amplifier or frequency multiplier. By using multiplier, multi function module can be realized amply in comparison to multi band module which has separate block for each frequency band. Some com paring analysis among the switching method between separate amplifier and multiplier, the structure using frequency selective reflector, and the module using the defected ground structure. The multi function module which operates as amplifier or multiplier with input frequency is developed and input frequency suppression and output harmonics suppression can be improve d by using defected ground structure.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.3
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• pp.247-252
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• 2013

In this paper, a microwave tag system of a frequency-scanning type is proposed with multi-resonators using defected ground structures. While a conventional chip-based RFID stores time-sequential codes, the proposed type achieves pure passive tags by using multi-resonant bits over a frequency range. Moreover, the resonators of the spiral defected ground structures implemented on the back side of transmission lines have advantages of the excellent bandstop characteristics as well as the bit-error avoidance by the re-radiation on normal resonators. The proposed microwave tag is designed with UWB antennas at 3~7 GHz. From the experimental results in an anechoic chamber, it has been verified of the excellent recognitions for various 5-bits identification codes.