• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.772-773
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• 2011

발전단지내 발전소와 변전소 접지망이 서로 연결되지 않고 독립적으로 구성된 경우 설비보호를 위한 보호회로가 큰 대지전위 차로 인해 손상되거나 보호설비가 오동작할 우려가 있다. 본 논문에서는 독립된 접지망간 연결된 보호회로에 대지전위 차로 인해 발생할 수 있는 문제를 분석하였으며 고장전류가 유입된 접지망 전위가 상승하면 CT(Current Transformer)회로가 이중접지 된 곳에서는 보호회로가 오동작할 수 있는 조건이 형성되고, 이중접지가 안되었다 할지라도 대지전위 상승이 회로를 통해 전달되어 회로와 외함간 절연파괴가 일어날 수 있으므로 보호회로 케이블이 발전소와 변전소간 연결된 곳에서는 반드시 접지망을 연결하여야 한다는 것을 확인할 수 있었다.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1242-1244
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• 2001

전철화 선로에 있어서 공동 접지 방식은 Staff 안전과 선로변 전기 설비에 가장 큰 영향을 인가하는 귀선 전류에 따른 문제점을 해결할 수 있는 최상의 방식으로 평가되고 있으며, 이들 접지 시스템의 구성은 기존의 전력 공급 시스템에 기본을 두고, 전철화에 따라 선택된 궤도 회로의 특성에 의해 모든 설계 변수가 변화되는 원리가 적용된다. 본 논문에서는 이러한 견지에 입각하여 궤도 회로에 의한 공동 접지망 구성 요소를 프랑스 철도청(SNCF)의 규정에 의해 분석한 후, 이를 경부선 전철화 구간에 적용하여 관련 설계 변수를 결정하였다.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.4 no.1
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• pp.46-53
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• 1990

GIS(Gas-Insulated Switchgear)형 옥내변전소에 있어서 접지계의 구성은 접지도체를 포설할 수 있는 면적이 협소하기 때문에 특별한 설계방법이 요구된다. 본 논문에서는 접지망의 전위해석과 축소형 변전소의 접지계 설계기법을 제시하였고, 아울러 컴퓨터 시뮬레이션을 위한 프로그램을 작성하고 그 시뮬레이션 결과를 측정치와 비교하여 프로그램의 타당성을 입증하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.12
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• pp.4968-4974
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• 2010

Electrical Railroads provide electric power, which can operate vehicles, via feeder wires. And the supplied current returns to the transformer substation through lines and ground net. In domestic cases, the configuration of ground net affecting such a return current mostly uses an exclusive earth method. However, along with the introduction to Gyeongbu HSL(High Speed Line), the concept of Common Earth was applied to Electrical Railroads. In this paper, based on the return currents analyzed to be measured in the electrified sections for the operation of High Speed Rails in existing lines, we analyze the relations between earth methods and return currents in electrified sections. For analysis, we utilize the measured values of return currents measured in track circuits in Gyeongbu HSL, and predictive values of those compared to the earth methods between Gyeongbu HSL and the existing electrified sections.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.9
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• pp.509-514
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• 2002

The aim of this research is to find out how the common earth network affects the level of the traction return current in the $2{\times}25 kV$ Power Supply System. The traction return current plays a significant role in the operation of the facilities near the rails. It is shown that the common earth network in the $2{\times}25 kV$ power supply system not only minimizes the level of the traction return current, but also increases the safety of the working crew on the railways. In order to determine the relationship between common earth network and the traction return current, we investigated the earth system of the Gyongbu High Speed Line that is constructed following the SNCF regulations. We carried out the field test in the Osong station. The results of the test show that the common earth network minimizes the effect of the traction return current. We also find that the simulated results are very similar to the test results. We concluded that the results of the test can be applied for the rest of the Gyongbu High Speed Line under construction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.2343-2348
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• 2014

Main ground net of power plant is formed to protect human body from increase in potential gradient caused by grounding current during ground fault. Calculations during ground design are generally performed according to IEEE Std-80-2000 (Kepco Design Standard 2602). However, it is difficult to apply this Standard to water environment, and a grounding technology is required to secure grounding resistance of floating photovoltaic system. Therefore the aim of this paper is to investigate and analyze ground resistivity on the water surface and underwater of reservoir using Wenner 4-pin method, a general method of measuring ground resistivity. Also, grounding resistance of floating photovoltaic systems currently in operation was measured and analyzed using the voltage drop method suggested in the international standard (IEEE Std-81) to propose a grounding method for stable grounding of floating photovoltaic system. The resistivity at 1m below the surface of water ($126.3969[{\Omega}{\cdot}m]$) is mostly higher than resistivity at the river bed ($97.5713[{\Omega}{\cdot}m]$). Also the proposed grounding anchor method was determined as the most effective method of securing stable grounding resistance in floating photovoltaic systems and is expected to be utilized as a ground method for future floating photovoltaic generation systems.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.190-195
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• 2008

Surge proof equipment is an installation to make surge flow on the ground promptly so as to reduce surge-related damage on infrastructure, not to prevent surge from falling down on infrastructure directly. Compared with classical line individual earth, High speed line common earth has higher surge characteristic and plays a significant role to prevent infrastructure damage and injuries from surge, or short circuit accident between 25kV catenary and rail. In this paper, we analyzed the case of accident that caused communication/signaling system impaired while a tractor crossing level crossing at Honam line; in addition, we examined the accident reduction measures to minimize injury and property damage from cutting accidents with respect to common earth network.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.8
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• pp.49-58
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• 2015

A floating type of memristor emulator which acts like the behavior of $TiO_2$ memristor has been developed. Most of existing memristor emulators are grounded type which is built disregarding the connectivity with other memristor or other devices. The developed memristor emulator is a floating type whose output does not need to be grounded. Therefore, the emulator is able to be connected with other devices and be utilized for the interoperability test with various other circuits. To prove the floating function of the proposed memristor emulator, a Wheatstone bridge is built by connecting 4 memristor emulators in series and parallel. Also this bridge circuit suggest that it is possible to weight calculation of the neural network synapse.

• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.1
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• pp.36-44
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• 2006

In this study, we constructed a forest fire danger map in the Yeongdong area of Gangwon-do and Northeastern area of Gyeongsangbuk-do using a forest fire rating model and geographical information system (GIS). We investigated the appropriate positions of the automatic weather station (AWS) and a comprehensive network solution (a system including measurement, communication and data processing) for the establishment of an optimum mountain meteorological observation network system (MMONS). Also, we suggested a possible plan for combining the MMONS with unmanned monitoring camera systems and wireless relay towers operated by local governments and the Korea Forest Service for prevention of forest fire.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.10
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• pp.1071-1078
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• 2003

In this paper, the planar, compact, and broadband phased array antenna system for IMT-2000 applications has been investigated. Two methods far designing a low-cost and low-complex beam-farming network are proposed. First, a new compact and broadband phase shifter with continuously controlled phase bits is designed by using parallel coupled lines. Second, its equivalent phase delay line is suggested to be capable of replacing the complex phase shifter with a reference phase bit on a phased array antenna. For the purpose of achieving the broadband system, in addition to the broadband phase shifter, a wide-slot antenna with a ground reflector is utilized as an element antenna. Therefore, the phased array antenna system has achieved compact size, broad bandwidth, and wide steering angle, although it has low complexity and low fabrication cost. The 3${\times}$1 phased array antenna system has a compact size of 1.6 λ${\times}$ l.6 λ, which is the sufficient ground plane of the wide-slot antenna. Experimental results present that the S$\_$11/ has less than 15 dB within the band and its radiation patterns on an E-plane have the capability of steering an antenna beam from -29$^{\circ}$to +30$^{\circ}$.