• Title/Summary/Keyword: Electric shielding

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Study on the Between the Grounding Resistance and Grounding Electrode using Mesh Grounding Electrodes and a Shielding Panel (메쉬접지전극과 차폐패넬을 이용한 접지저항 및 접지전극간의 영향에 관한 연구)

  • Leeg, Chung-sik;Cho, Moon-taek;Na, Seung-kwon
    • Journal of Advanced Navigation Technology
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    • v.19 no.3
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    • pp.230-236
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    • 2015
  • In this paper, the electric potential of electrode surface is investigated by assuming them as two dimensional sets of point current sources. And, the simulated water tank is manufactured as a reduced scale of the earth. Henceforth, the adequate model electrode for test is decided to decrease experimental errors relevant to the limitation of the size of the water tank. The one of important things of this work, the deduction method of the potential interference factor is proposed, which used as the criterion of the potential interference according to the shape of conductors and the laying conditions, when multiple grounding conductors are situated at the same resistance grounding area. Also, the validity of this theory is verified from a numerical simulation of the grounding electrode to be used in experiments, and this study is realized by the verified theory and the simulated experiments.

Fabrication of $V_2O_5$ Nanowire/PVA (Polyvinyl Alcohol) Composites for the Electric Applications (전기적 응용을 위한 바나듐옥사이드 나노선/폴리비닐 알코올 복합체 제작)

  • Lee, Jae-Woo;Lee, Kang-Ho;Kim, Gyu-Tae
    • Journal of IKEEE
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    • v.13 no.2
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    • pp.216-219
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    • 2009
  • $V_2O_5$ nanowire / polyvinyl alcohol (PVA) polymer composite fibers were fabricated by a new simple method. The reaction of PVA and acetone facilitates the formation of the polymer membrane which can be used to make the fiber. Composite fiber is percolative in the conductance because of the low percolation threshold in $V_2O_5$ nanowire networks. The fiber composite can be applied to the electromagnetic shielding originating from the conductive nature.

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Study to Analyze the Grounding System in the 20 kHz Power Installation (20 kHz 전력설비 접지시스템 분석에 관한 연구)

  • Jung, Jin-Soo;Han, Woon-Ki;Park, Chan-Urm;Song, Young-Sang;Lim, Hyun-Sung
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.9
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    • pp.1308-1312
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    • 2013
  • In this paper, carried out for optimal ground system for ensuring safety for electricity used to power equipment in the 20 kHz frequency. Now the grounding system of the mesh electrode, electrode rods are installed for power plant safety and protection against electric shock. However, the electrical equipment grounding system in the 20 kHz were considering the increasing grounding impedance due to the high frequency and the magnetic shielding. But until now, there has been little research on the grounding system. To solve this problem, In this paper was proposed optimal grounding system due to the experiment using a mesh electrode, rod electrode, aluminum plate electrodes. Measurement results, grounding resistance was depending on the material of the electrode grounding resistance. In addition, the leakage current (induced) appeared to be affected depending on the type of electrode.

The Anaysis of the Fault Currents According to Core-Saturation and Fault Angles in an Magnetic Shielding Type High-Tc Superconducting Fault Current Limiter (고온초전도한류기가 도입된 회로의 철심 포화와 사고각에 따른 사고전류 해석)

  • Lee, Chan-Joo;Lee, Seung-Je;Jang, Mi-Hye;Kim, Tae-Jung;Hyun, Ok-Bae;Ko, Tae-Kuk
    • 한국초전도학회:학술대회논문집
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    • v.9
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    • pp.401-404
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    • 1999
  • 본 논문은 고온초전도한류기가 투입된 회로에 사고가 발생했을 경우 사고각에 따른 사고전류의 패턴에 관한 연구이다. 계통에 심각한 영향을 끼치는 이러한 사고전류의 순간 특성을 해석하기 위해 유도형 고온초전도한류기를 직접 제작하였으며 임의로 다른 각도에서 사고를 발생시켜 실험하였다. 임의의 사고각을 위해 triac으로 구성되어있는 위상각제어 및 사고 발생기를 부하와 직렬로 연결하였다. 또한, 순간적으로 큰 사고전류의 유입은 철심을 포화시키기에 충분하며 철심의 포화로 인해 상대투자율이 작아짐으로서 고온초전도한류기의 임피던스가 작게 발생하게 된다. 본 논문에서는 이러한 영향으로 인한 사고전류의 패턴에 관하여 연구하였다.

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A Study on the Step Response Characteristics in Shielded Resistor Divider for Switching Impulse Voltage (개폐 충격전압 측정용 쉴드 저항분압기의 직각파 특성에 관한 연구)

  • Kim, Ik-Su;Lee, Hyeong-Ho;Jo, Jeong-Su;Park, Jeong-Hu
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.48 no.12
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    • pp.777-784
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    • 1999
  • Since the ultra-high voltage power apparatus are recommended to withstand switching surge generated from the electric power system, the switching impulse voltage is generally used to verify this requirement at the testing laboratories. Recently, the international standard(IEC 60060-2) related to the high voltage measurement techniques is revised requiring a traceability of measuring system for high voltage measurements. In this paper, a reference divider for switching impulse voltage is developed satisfying the revised. IEC standard and the possibility of applications has been investigated. Therefore, the characteristics of the high and low voltage side resistor and the shielding ring have been analyzed including the step response characteristics of the prototype divider. Throughout various efforts, it is confirmed that our measuring device has shown compatible characteristics as a reference divider.

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Dielectric Characteristics of the Polymers Containing Nano-size Conductive Carbon Black Powders (전도성 나노 카본 블랙을 함유한 고분자 재료의 유전특성)

  • 진우석;이대길
    • Composites Research
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    • v.17 no.5
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    • pp.68-77
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    • 2004
  • The electromagnetic (EM) absorption or shielding characteristics of a material is an important issue not only for military purpose but also for commercial purposes such as radar, electric or telecommunication devices. In order to design the effective electromagnetic wave absorber, the electromagnetic characteristics of the constituents of the material should be available in target frequency band. Also, it must be possible to predict the electromagnetic properties of absorbers with respect to the content of lossy ingredients. In this study, the dielectric properties of unsaturated polyester resins containing nano-size conductive carbon black powder were measured with a free space method in the X-band frequency range and analyzed with respect to the content of carbon black. Finally, the method for estimating the dielectric properties of polymeric resin containing conductive carbon black with respect to the EM frequency was developed and verified.

Effect of Pre-immersion Time on Electrophoretic Deposition of Paint on AZ31 Magnesium Alloy

  • Van Phuong, Nguyen;Moon, Sungmo
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2014.11a
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    • pp.45-45
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    • 2014
  • The importance of magnesium alloys has significantly increased due to their low density, high strength/weight ratio, very good electromagnetic shielding features and good recyclability. However, unfortunately, Mg alloys are very susceptible to corrosion due to their high chemically activities (= -2.356 V vs. NHE at $25^{\circ}C$), hence, most commercial Mg alloys require corrosion protective coatings. Organic coating such as painting, powder coating and electrophoretic deposition of paint (E-paint) is typically used in the final stages of the coating process of Mg alloys. In this study, effect of pre-immersion time on the deposition of E-paint on AZ31 Mg alloy was investigated. It was found that during pre-immersion time, AZ31 Mg alloy rapidly reacts with E-paint solution and paint can be self-deposited on the AZ31 surface without applying of electric current. The pore size on the E-painted AZ31 Mg alloy increased with increasing pre-immersion time from 0 to 5 min. Both adhesion and corrosion resistance of E-painted AZ31 Mg alloy decreased with increasing pre-immersion time. The best E-paint AZ31 Mg alloy, which showed stronger adhesion after water immersion test and good corrosion resistance, was started to deposit after 5 s of pre-immersion time.

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Analysis of Resonant Characteristics for a Metallic Shielding Enclosure with a PCB Source (PCB 파원이 내장된 금속 함체의 공진 특성 해석)

  • Cho, Byung-Doo;Kim, Ki-Chai
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.23 no.4
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    • pp.507-514
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    • 2012
  • This paper proposed the analysis method of the cavity resonance characteristics for a metallic enclosure with a PCB trace source. In order to calculation the electromagnetic fields inside the cavity, coupled integral equations for a current distribution on the PCB trace and an aperture electric field distribution on the boundary of the PCB dielectric are derived and solved by applying Galerkin's method of moments. The result show that the resonant characteristics of the metallic enclosure are fairly good agreement with the simulation(HFSS) and the measured results. The resonant frequencies of the metallic enclosure with the PCB trace are changed by the PCB trace location inside of the cavity. In order to check the validity of the theoretical analysis, the calculated return losses are compared with the measured results.

Design and Fabrication of an Ultra-low Partial Discharge Measurement System (극미소 부분방전 측정시스템의 설계 및 제작)

  • Seo, Hwang-Dong;Song, Jae-Yong;Moon, Seung-Bo;Kil, Gyung-Suk;Kwon, Jang-Woo
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • v.9 no.2
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    • pp.208-211
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    • 2005
  • This paper presents an ultra-low partial discharge(PD) measurement system that has been accepted as a non-destructive method to estimate electrical insulation of low-voltage electric devices. The PD measurement system is composed of a coupling network, a low noise amplifier, and associated electronics. A shielding box is used to make a better condition against electromagnetic interference. A low cut-off frequency of the coupling network was 1MHz(-3 dB). Calibration tests on laboratory set-up have shown that the PD measurement system has a stable sensitivity of 11.4mV/pC. In an application experiment on a low-voltage induction motor(5HP), we could detect 0.77pC level of partial discharge pulse at the applied voltage of AC 664 V$_{peak}$.

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A Study on Grounding Technology for the Reduction of Electric Surge in IBS Building (IBS 빌딩에서의 서어지 저감을 위한 접지방안 연구)

  • 박중양;김학련;최규형
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2003.11a
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    • pp.87-92
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    • 2003
  • According to the realization of highly information dependent society, the recent building system is developed into the concept of suitable for management of intellegent work, which is demanded to unify of IBS(Intelligent Building System), IC(information communication), OA(office automation), BA(building automation) system and computer technology. However inspite of the presence arrester, cable shielding, insulated TR, filter, earth etc., in the IBS building for the cope with several surge and noise has several problems from the wrong operation of the equipment which caused from several surge, damage of equipment, and noise etc. And the miss operation caused by wrong earth works, which must be considered at first during the building construction. In order to minimize these problems, it's necessary that various earth project are performed effectively, and bonding methods between the mutual wiring of earth system and the equipments in the building should be improved sucessively. So in this paper, we analyze present domestic conditions of the earth technology in IBS building, and propose minimization method for the various surge and noise problem, and examine and analyze through the applied works.

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