• Title/Summary/Keyword: ground impedance

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Prediction of the Specific flow resistivity of the Ground Surface by Acoustical Method (음향학적 방법에 의한 지표면의 유동 비저항 예측)

  • 황철호;정성수;은희준
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1997.10a
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    • pp.237-243
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    • 1997
  • Most outdoor sounds go from sources relatively near the ground to receivers near the ground. When either source or receiver are near the ground, interference can occur between the direct sound and that reflected at the ground which travels a slightly longer path. The sound pressure at the receiver is very different depending on the state of ground surface i.e. ground impedance. Ground impedances could be characterized by the value of a single parameter, namely the flow resistivity of the ground surface. This study suggests the measurement method of the flow resistivity using two microphones and predicts the flow resistivities of various ground surfaces.

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Grounding Characteristics Analysis of the Stainless-steel Plate Grounding Electrode for Distribution Poles (배전전주용 스테인리스강판 접지전극의 접지 특성분석)

  • Kim, Kyung-Chul;Lee, Kyu-Jin;Kim, Min-Sung;Jung, Ji-Won
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.8
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    • pp.94-100
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    • 2010
  • Grounding system insures a reference potential point for electric devices and also provides a low impedance path for fault currents or transient currents in the earth. The ground impedance as function of frequency is necessary for determining its performance since fault currents could contain a wide range of frequencies. In this paper, the grounding resistance, grounding impedance and transient grounding impedance are measured by using 3-point fall-of-potential method in order to analyse grounding characteristics of the stainless-steel plate grounding electrode. An equivalent transfer function model of the grounding impedance and transient grounding impedance are identified from the measured values by using ARMA method and evaluated by comparing conventional grounding impedances.

Effect of static and dynamic impedance functions on the parametric analysis of SSI system

  • Maroua Lagaguine;Badreddine Sbarta
    • Coupled systems mechanics
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    • v.13 no.4
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    • pp.293-310
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    • 2024
  • This paper investigates the dynamic response of structures during earthquakes and provides a clear understanding of soil-structure interaction phenomena. It analyses various parameters, comprising ground shear wave velocity and structure properties. The effect of soil impedance function form on the structural response of the system through the use of springs and dashpots with two frequency cases: independent and dependent frequencies. The superstructure and the ground were modeled linearly. Using the substructure method, two different approaches are used in this study. The first is an analytical formulation based on the dynamic equilibrium of the soil-structure system modeled by an analog model with three degrees of freedom. The second is a numerical analysis generated with 2D finite element modeling using ABAQUS software. The superstructure is represented as a SDOF system in all the SSI models assessed. This analysis establishes the key parameters affecting the soil-structure interaction and their effects. The different results obtained from the analysis are compared for each studied case (frequency-independent and frequency-dependent impedance functions). The achieved results confirm the sensitivity of buildings to soil-structure interaction and highlight the various factors and effects, such as soil and structure properties, specifically the shear wave velocity, the height and mass of the structure. Excitation frequency, and the foundation anchoring height, also has a significant impact on the fundamental parameters and the response of the coupled system at the same time. On the other hand, it have been demonstrated that the impedance function forms play a critical role in the accurate evaluation of structural behavior during seismic excitation. As a result, the evaluation of SSI effects on structural response must take into account the dynamic properties of the structure and soil accordingly.

Analysis of Transient Potential Rises of Horizontal Ground Electrodes Considering the Frequency-Dependent of Soil (토양의 주파수의존성을 고려한 정보통신설비용 수평접지전극의 과도전위상승 분석)

  • Ahn, Chang Hwan
    • Journal of the Institute of Electronics and Information Engineers
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    • v.53 no.2
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    • pp.147-153
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    • 2016
  • The lightning protection of information and communication facilities is very important factor to improve a reliability of the action of these equipment. Especially the transient potential rise of ground electrode being injected with the lightning current is to be a basic data of the dielectric strength for both power and communication facilities so that more accurate analysis should be required. The transient potential rise can be calculated from the ground impedance and the ground impedance is strongly dependent upon the shape of the ground electrode and the frequency-dependence of soil. The Debye's equation which is able to calculate the characteristics of dielectrics is used to analyze the frequency-dependent of soil. Also, the method to calculate the transient potential rise from the ground impedance is specified in this paper. In order to analyze the transient potential rise resulting from calculations with Debye's equation, TLM(transmission line method) and case of ${\rho}$(resistivity)-constant are simulated, respectively. The length of a horizontal ground electrode is 30 m and simulations were performed at 10, 100, $1000{\Omega}{\cdot}m$ with the standard lightning current waveform. In result, the transient potential rise of horizontal ground electrode calculating with Debye's equation is lower than it of other models.

Impulse Ground Impedances of a Deeply Driven Ground Rod Combined with Different Shape Grounding Electrodes (형상이 다른 접지전극에 접속된 심매설 봉상 접지전극의 임펄스접지임피던스 특성)

  • Lee, Bok-Hee;Lee, Su-Bong;Chang, Keun-Chul
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.19 no.2
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    • pp.63-68
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    • 2005
  • This paper describes the characteristics of effective impulse ground impedance of deeply driven ground rods combined with grounding grid or counterpoises with needles. The potential rises of the test ground electrodes were measured as a function of the rise time of applied impulse currents and the effective impulse ground impedances were calculated The impulse ground impedances of deeply driven ground rods strongly depend on the rise time of impulse currents and significantly reduced by the connection of grounding grids in parallel.

Stepped Impedance LPF Using MCS Line with Ground (접지가 있는 MCS 선로를 이용한 스텝 임피던스 저역 필터)

  • Rhee, Seung-Yeop;Lee, Yong-Kook
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.19 no.11
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    • pp.1248-1253
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    • 2008
  • The MCS(Micro-Coplanar Strip) line with ground has been analyzed. The conformal mapping method is used to calculate the quasi-static effective dielectric constant and characteristic impedance of this MCS line. The computed results of the present work are found to be in good agreement when compared with the results obtained using commercial S/W, IE3D. And in this paper, the stepped-impedance low pass filter is designed and fabricated with MCS lines for improving the frequency responses. The LPF proposed structure has been also designed and implemented to have the sharp attenuation characteristics in stop band. The agreement between simulation and measurement results verify the implemented LPF.

High Impedance Fault Detection on 22.9kV Multigrounded Distribution System (22.9kV 이중접지 배전선로 고저항 지락 검출)

  • Park, Young-Moon;Lee, Ki-Won;Lim, Ju-Il;Yoon, Man-Chul;Yoo, Myeong-Ho
    • Proceedings of the KIEE Conference
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    • 1987.11a
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    • pp.463-468
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    • 1987
  • In this paper, a high impedance fault detection on 22.9kV multigrounded distribution system that has been very difficult by any existing conventional protective relaying systems is studied. Because the fault current is very low, it cannot be distinguished from neutral current caused by load unvalanced on multigrounded distribution system. We developed the new and best algorithms of high impedance ground fault detection. This algorithms are 'the even order power method, even order ratio method', 'and even order ratio varience method'. Using this algorithms, a detection device for high impedance faults is constructed and tested in the laboratory. And continually, it is installed and has been tested in KEPCO substations.

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RF Loss Minimization Method Using High Impedance Filter for Research (High Impedance Filter를 이용한 RF Loss 최소화 방법에 대한 연구)

  • Wang, Hyun-Chul;Seo, Hwa-Il
    • Journal of the Semiconductor & Display Technology
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    • v.19 no.1
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    • pp.55-60
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    • 2020
  • This study designed High impedance filter to reduce RF loss to heater heating wire and increase RF current flowing to heater ground wire. Effects such as D / R improvement and process reproducibility could be seen. In addition, RF parameter distribution optimization was possible by understanding the RF path of PE-CVD equipment using Plasma and designing filter.

Comparison of Impedance Characteristics of Copper- and Carbon-Eearth Electrode by Application of Various Current Source (다양한 전류원에서 접지동봉과 탄소접지극의 임피던스 특성 비교)

  • Kim, Hwang-Kuk;Moon, Byung-Doo;Ji, Hong-Keun;Park, Dae-Won;Kil, Gyung-Suk
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2008.10a
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    • pp.293-296
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    • 2008
  • In this paper, we carried out an comparative analysis on ground impedance of single copper-, three linked copper- and single carbon- electrodes by the application of various current sources such as sine, square, and surge with fast risetime. Impedance of single-copper electrode was the highest among them and was affected as the amplitude and the frequency of applied current. However, impedance characteristics of the three linked copper- and the single carbon- electrodes showed a similar tendency.

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A New Distance Relaying Algorithm Immune to Mutual Coupling Effect and Reactance Effect for 765kV Untransposed Parallel Transmission Lines (상호결합효과와 리액턴스효과를 제거한 765kV 비연가 송전선로 보호용 거리계전 알고리즘)

  • Ahn Yong-Jin;Kang Sang-Hee
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.54 no.1
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    • pp.25-30
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    • 2005
  • An accurate digital distance relaying algorithm which is immune to mutual coupling effect and reactance effect of the fault resistance and the load current for the line faults in 765kV untransposed transmission lines is proposed. The algorithm can estimate adaptively the impedance to a fault point independent of the fault resistance. To compensate the magnitude and phase of the apparent impedance, this algorithm uses the angle of an impedance deviation vector. The impedance correction algorithm for phase-to-ground fault and phase-to-phase short fault use a voltage equation at fault point to compensate the fault current at fault point. A series of tests using EMTP output data in a 765kV untransposed transmission lines have proved the accuracy and effectiveness of the proposed algorithm.