• Title/Summary/Keyword: ground impedance

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A Miniaturized Broadband Impedance Transformer Employing Periodic Ground Structure for Application to Silicon RFIC (주기적 접지구조를 이용한 실리콘 RFIC용 광대역 소형 임피던스 변환기)

  • Young, Yun
    • Journal of Advanced Marine Engineering and Technology
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    • v.35 no.4
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    • pp.483-490
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    • 2011
  • Using a coplanar waveguide employing periodic ground structure (PGS) on silicon substrate, a highly miniaturized and broadband impedance transformer was developed for application to low impedance matching in broadband. Concretely, the multi-section transformer was designed using Chebyshev polynomials design technique for ultra broadband operation. Its size was 0.026 $m^2$ on silicon substrate, which was 8.7 % of the one fabricated by conventional coplanar waveguide on silicon substrate. The transformer showed a good RF performance over a ultra broadband from 8 - 49.5 GHz.

Highly Miniaturized and Low impedance Wilkinson Power Divider on RFIC/MMIC for application to IT components of Ocean Engineering (해양 IT 소자에의 응용을 위한 RFIC/MMIC용 초소형 저임피던스 윌킨슨 전력분배기 설계)

  • Kim, Choong-Ryul;Yun, Young
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2005.06a
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    • pp.412-416
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    • 2005
  • In this paper we propose low-impedance and miniaturized a wilkinson power divider on MMIC passive component which was fabricated by a novel microstrip line structure employing periodically perforated ground metal (PPGM). The novel microstrip line structure showed much lower impedance and shorter guided-wavelength than conventional one. Using the novel microstrip line with periodically perforated ground metal, a miniaturized 17 ${\Omega}$ power divider was fabricated. The line width of the power divider was 20 ${\mu}m$, and the size of it was 0.110 $mm^2$, which is 21 % of conventional one. The power divider exhibited good RF performances from 10 to 20 GHz.

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A New Distance Relaying Algorithm for Phase-to-Ground Fault in 765kV Untransposed Transmission Lines (765kV 비연가 송전선로에서 단상지락고장 시어 거리개전 알고리즘)

  • AHN YONG JIN;KANG SANG HEE
    • Proceedings of the KIEE Conference
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    • summer
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    • pp.452-454
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    • 2004
  • An accurate digital distance relaying algorithm which is immune to reactance effect of the fault resistance and the load current for phase-to-ground fault 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 uses 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.

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Characteristics for Ground Impedance according to Distance of Current Probe and Frequency (전류보조전극 거리 및 주파수에 따른 접지임피던스 특성)

  • Gil, Hyoung-Jun;Lee, Ki-Yeon;Moon, Hyun-Wook
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.5
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    • pp.122-128
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    • 2010
  • This paper presents the characteristics for ground impedance of combined three rods according to distance of current probe and frequency using the fall-of-potential method and the testing techniques to minimize the measuring errors are proposed. The fall-of-potential method is theoretically based on the potential and current measuring principle and the measuring error is primarily caused by the position of auxiliary probes. In order to analyze the effects of ground impedance due to the distance of the current probe and frequency, ground impedances were measured in case that the distance of current probe was located from 5[m] to 20[m] and the measuring frequency was ranged in 55~513[Hz]. The results could be help to determine the position of current probe and the measuring frequency when the ground impedance was measured at grounding system.

A Study on the Characteristic of Variable Impedance Line using DGS (DGS를 이용한 가변 임피던스 선로 특성에 관한 연구)

  • Kim Young-Ju;Joung Myoung-Sub;Park Jun-Seok;Cho Hong-Goo
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.54 no.1
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    • pp.35-40
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    • 2005
  • In this paper, we designed and fabricated the variable impedance line by using the DGS(Defected Ground Structure) which is useful in mounting the external lumped elements. Also we used a varactor diode as Control device stuff at the proposed variable impedance line. We are able to change the impedance of transmission line as varied the capacitance of varactor diode by adjusting DC bias. The impedance variation of the proposed DGS line is about maximum 70 Ω. We will study about the application of DAM(Direct antenna modulation) in the future work.

Characteristics of Grounding Impedances of Carbon Compound Grounding Electrodes (탄소혼합물 접지전극의 접지임피던스의 특성)

  • Lee, Kang-Soo;Lee, Bok-Hee
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.25 no.5
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    • pp.54-60
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    • 2011
  • This paper presents characteristics of frequency-dependent grounding impedance and transient grounding impedance for the carbon compound grounding electrode used in the installation of computerized electronic equipment and lightning protection system. The frequency-dependent grounding impedances were measured by applying sinusoidal currents in the frequency range from 100 [Hz] to 10[MHz], and the transient grounding impedances were examined by subjecting the impulse current with the front-time between 1~80[${\mu}s$]. As a result, the ground resistance of the carbon compound grounding electrode is less than that of another type grounding electrodes. The transient grounding impedance is relatively low and the conventional grounding impedance is rather lower than the ground resistance. The frequency-dependent grounding impedance of the carbon compound grounding electrode is capacitive and the grounding impedance is decreased with increasing the frequency of injected currents. Therefore in the case that the carbon compound grounding electrode is jointly used with large-scaled grounding electrodes, it is possible to reduce the high frequency grounding impedance of the integrated grounding electrode system.

Effects of the Length of Down Conductors on Transient Ground Impedances (인하도선의 길이가 과도접지임피던스에 미치는 영항)

  • Lee, Bok-Hee;Lee, Su-Bong;Jeong, Dong-Cheol
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.20 no.4
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    • pp.72-77
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    • 2006
  • This paper presents the transient impedance behaviors according to the length of down conductors of grounding systems to lightning impulse currents. The potential rise and effective impulse ground impedance of the deeply-driven ground rod and grounding grid subjected to the impulse currents were measured and analyzed as a function of the rise time of impulse currents and lengths of down conductor. The transient ground impedances strongly depend on the configuration and size of grounding electrodes, the waveform of impulse currents and the length of down conductors, and the installation methods reducing the inductance of down conductors are an important factor to decrease the transient ground impedances.

A Fast Computation Method of Power Ground Plane Impedance using the Mobius Transform (Mobius변환을 이용한 전력접지층 임피던스의 빠른 계산방법)

  • Suh Youngsuk;Kim In-Sung;Song Jae-Sung;Eum Tae-Su
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.54 no.1
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    • pp.41-44
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    • 2005
  • A new method to reduce the computation time in power/ground-plane analysis is proposed. The existing method using the two dimensional infinite series summation take a lot of computation time. The proposed method is based on the approximation of impedance in the frequency domain through the Mobius transform. This method shows the good accuracy and the high speed in computing. In the case of impedance calculation for 9'x4' board, the proposed method takes 0.16 second of computing time whereas the existing method takes 2.2 second. This method can be applied to the analysis and design of power/ground-plane that need a lot of computation steps.

The Experimental Study on the behavior of Ground Impedance in the frequency region (주파수영역에서의 접지임피던스에 대한 실증적 연구)

  • Kang, J.W.;Jung, G.J.;Jeong, J.K.;Yang, B.M.
    • Proceedings of the KIEE Conference
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    • 1997.11a
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    • pp.155-157
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    • 1997
  • This paper presents the results of an experimental investigation of ground impedance in the low frequency region regarding the transiant state on the soil and ground electrodes(rod, electric rod with needles, electric mesh). The grounding resistance playing an important part in substation grounding designs is measured. Especially, the reduction effect of ground impedance by using the electric rod with needles in the soils are presented.

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Behaviors of Impulse Ground Impedances Associated with the Current Injection Point in a Ground Rod (봉상 접지전극에시 전류유입위치에 따른 임펄스 접지임피던스의 특성)

  • Lee, Bok-Hee;Jeong, Dong-Cheol;Lee, Su-Bong
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.19 no.1
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    • pp.94-100
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    • 2005
  • This paper presents the behaviors of transient and effective impulse impedances of a long ground rod associated with the current injection points. The laboratory test for the time domain performance of actual-sized model ground rod subjected to a lightning stroke current has been carried out The transient ground impedances of long ground rods under impulse currents were higher than the ground resistance. Both of the ground resistance and the effective impulse ground impedance decrease with increasing the length of the ground rods. Also, the effective impulse ground impedances are significantly increased in fast rise time ranges. The reduction of the ground resistance is decisive to improve the impulse impedance characteristics of grounding systems. When the test current is injected at the bottom of ground rod, the oscillating pulses with high frequency are included on the wave front of ground rod potential and the effective impulse impedances are higher than any other cases.