• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.2025-2027
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• 2004

The grounding system design of the communication base station can be on the unfavorable conditions to induce the safe designing because of the limited area of the communication base station and the week point of surge caused by the given geographical condition such as the top point of mountain. In this paper, it is examined throughly about the way of safe designing that can reduce GPR(Ground Potential Rise) within the normal frequency band. And it is also considered the effective counter plan to cope with a transient phenomena that happen when surge of scores MHz-band inserted.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.566-570
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• 2001

Generally, grounding systems are responsible for the safe operation of a power system. Their performance guarantees equipment protection and personnel safety under condition of the limited ground potential rise and touch voltages as well as step voltages under ground fault conditions. Therefore, it is necessary to measure the ground resistance frequently for checking the performance of grounding system, In this paper the ground resistance measuring system using digital signal processor and high-performance L-C resonant band pass filter is presented. The signal current magnitude for measuring ground resistance in this system is $10^{-1}[A]\;to\;5\times10^{-2}[A]$ and the current frequency is 30[Hz].

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.321-323
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• 2008

전력설비에 대한 접지시스템의 근본 목적은 인체에 대한 안정성의 확립과 설비의 기능 향상을 위하여 사고 발생 시 고장 전류를 대지로 안전하고 신속하게 방전시키는데 그 목적이 있다. 풍력발전기 접지설계 시 고려해야 할 중요한 설계 요소는 토양조건, 대지저항률의 측정과 분석, 고장전류, 안전전압 결정 등이 있으며, 이러한 설계 파라미터 가운데 대지저항률은 접지설계 방법 및 물량에 미치는 영향이 결코 작지 않으므로 이에 대한 정확한 측정과 분석을 통하여 효율적인 접지 설계를 시행할 수 있어야 한다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.03b
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• pp.25-25
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• 2010

This paper describes the design and fabrication of a Risk Voltage Meter (RVM) which can analyze the step and touch voltages in grounding systems. The meter consists of a sine-wave power source which generates up to 300 [$V_{rms}$] in ranges of 45 [Hz]~1 [kHz], a 8 Ch. data acquisition module, and a personal computer. Also, a noise elimination method by a digital band-pass filter during measurement is proposed.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.361-362
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• 2008

접지시스템은 전력설비에 대하여 인체의 안전을 확보함과 동시에 기기 및 장치의 절연 파괴를 방지하고 통신 잡음을 제거하여 정보 전송의 양질화를 이루는 기능성 향상을 위한 시스템으로, 사고 발생시 대지를 통하여 고장 전류를 신속하게 방전함으로서 기준전위를 유지하는 것을 목적으로 하고 있다. 이러한 접지시스템의 계획과 시공에 있어서 도심지에서의 충분한 접지공사 부지를 확보하는 것은 현실적인 어려움이 있으므로, 건축물 기초 구조물을 접지극으로 활용하여 접지시스템의 효과를 증대 할 수 있는 방안을 제시하고자 한다.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.446-448
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• 2001

Railway electrification results in Electromagnetic Interference, which affects a life and a equipment. Therefore, a plan against EMI must be considered. This study presents accurate simulation to examine a reason rail potential rise and how to design ground connection and draw up a plan of an optimal buried grounding system according to section.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.6
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• pp.68-74
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• 2014

The electrical parameters of soils are highly dependent on the various factors such as types of soil, chemical compositions, moisture content, temperature, frequency, and so on. The analysis of soil parameters is of fundamental importance in design of grounding systems. In this paper, we present the experimental results of frequency-dependent impedance, resistivity, permittivity of soils as functions of types of soil and moisture content. The impedance and resistivity of soils are decreased as the moisture content and the frequency increase. In particular, the variation of the soil resistivity with the frequency is pronounced in the conditions of high resistivity and low moisture content. On the contrary, the permittivity of soils are sharply decreased with increasing the frequency below 10kHz and the frequency-dependent permittivity of soils are highly changed in the conditions of high moisture and low resistivity.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.8
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• pp.454-460
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• 2004

The effects of surge arresters for protection of transmission systems against direct lightning strokes have already been reviewed using Electromagnetic Transients Program(EMTP). Distribution lines are spanned in much larger area than transmission lines, and therefore, are more susceptible to lightning strokes. We have modelled the 22.9kV underground distribution cable systems that have arresters and grounding wires. And this paper analyzes the overvoltages on underground distribution cable systems when direct lightning strokes strike on the overhead grounding wire using EMTP. Then we investigated that (1) the effects of lightning stroke according to underground distribution cable length (2) voltages at the riser pole and at the cable terminal according to installation of arrester. This study will provide insulation coordination methods for reasonable systems design in 22.9kV underground distribution cable systems.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.295-297
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• 1998

This paper shows characteristics of fault current division factor $S_f$, which is a ratio of earth- return current to total fault current, at a substation fed exclusively by power cables under unsymmetrical fault condition, such as single line-to-ground fault. In substation grounding system design, $S_f$ is a very important factor determining GPR, touch and step voltage at a substation under fault condition. In case of substations fed by overhead lines, 40-60% of $S_f$ has been typically used, although it is a very conservative value with no other network conditions considered. It is authors' hope that $S_f$ presented in this paper could hopefully be a basic reference in designing of substation grounding system, especially for a substation fed exclusively by power cables.

• ETRI Journal
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• v.27 no.6
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• pp.697-707
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• 2005

This paper proposes a new design of directional couplers with high directivity for personal communication services (PCS) and International Mobile Telecommunications-2000 (IMT-2000). The directional coupler is used to check and verify the power, frequency, and antenna reflection of a signal at transmission stations for mobile communications. The performance requirements of directional couplers are a strong coupling to reduce the effect on the transmitted power and high directivity to suppress the interference of the reflected signals and reduce the errors in communication. So far, various architectures have been proposed to gain high directivity, and there have been many studies used to obtain a strong coupling. However, conventional architectures for high directivity and strong coupling have a directivity of only about 20 dB, and there have been difficulties to achieve the higher directivity of 30 dB suitable for PCS and IMT-2000. This paper proposes a new architecture of directional couplers based on a grounding composed of strip lines, and compares the test results of this directional coupler with conventional ones. The results show that the proposed directional coupler has a directivity of more than 30 dB and is adequate for PCS and IMT-2000.