• 한국항해학회지
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• 제21권2호
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• pp.69-75
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• 1997

A modern electric system located at a certain distance from the discharge may respond with unexpected sensitivity, when an electrostatic discharge (ESD) phenomenon occurs heteronomously between metallic objects. For analyzing the transient electromagnetic fields caused by ESD, two resistance formulas - Toepler and Rompe-Weizel -are introduced. The experimental result given by Wilson-Ma are used to compare which of these resistance formulas is proper.

• 전자공학회논문지D
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• 제34D권12호
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• pp.1-7
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• 1997

Serious troubles may occur in electromagnetic equipments due to electrostatic discharge (ESD). The number of the damaging incidents are significantly increasing with the increased use of integrated semiconductor elements with loer operation pwoer. In order to examine the phenomena theoretically, this paper anlyzes properties of the transient electromagnetic fields rdiated by ESD. A new model is presented using the Rompe-weizel formula for the spark resistance. The numerical results of ESD fields are compared with the experimental data that were given by wilson-Ma.

• Journal of Electrical Engineering and Technology
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• 제2권3호
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• pp.306-311
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• 2007

The transient fields generated during switching operations in a Gas Insulated Substation (GIS) are associated with high frequency components in the order of few tens of MHz. These transient fields leak into the external environment of the gas-insulated equipment and can interfere with the nearby electronics. Measurements of the transient fields are thus required to characterise the interference caused by switching phenomena in such substations. In view of the above, E-field emission measurement during a switching operation has been carried out for a 245 kV GIS model, using a resonant dipole antenna and D-dot sensor. The characteristics of the E-fields i.e., frequency spectra and their levels have been analysed and are reported in the paper. Suitability of the measurements has been confirmed by comparing frequency spectra of the measured and computed transient fields.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기물성,응용부문
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• pp.255-257
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• 2004

This paper was studied electromagnetic field distribution and damping of PD(Partial Discharge) signal in GIS(Gas Insulated Switchgear). Cut-off frequency of electromagnetic wave propagation modes were computed, electromagnetic field distribution of propagation modes in GIS by FEM(Finite Element Method) were simulated and simulated damping characteristic of electromagnetic waves in GIS by EMTP(Electromagnetic Transient Program) when generated PD pulse. Frequency band of $TE_{mn}/TM_{mn}$ modes were determinated by simulation results of electromagnetic field distribution and were discussed optimal position of UHF sensor from this results. Equivalent circuit was used to simulate signal damping of PD pulse in GIS by EMTP and compared with measured results in laboratory of KERI.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권4호
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• pp.185-191
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• 2003

In this Paper, we propose an accurate and stable solution of the transient electromagnetic response from three-dimensional arbitrarily shaped conducting objects by using a time domain magnetic field integral equation. This method does not utilize the conventional marching-on in time (MOT) solution. Instead we solve the time domain integral equation by expressing the transient behavior of the induced current in terms of temporal expansion functions with decaying exponential functions and Laguerre·polynomials. Since these temporal expansion functions converge to zero as time progresses, the transient response of the induced current does not have a late time oscillation and converges to zero unconditionally. To show the validity of the proposed method, we solve a time domain magnetic field integral equation for three closed conducting objects and compare the results of Mie solution and the inverse discrete Fourier transform (IDFT) of the solution obtained in the frequency domain.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2001년도 학술대회논문집
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• pp.59-64
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• 2001

Transient in an electrical system are generated by lightning and switching. This paper presents analysis of switching and lightning surge, and means of limiting the voltage magnification transient for high voltage power systems by using EDSA's EMTAP software package. One means of limiting the voltage magnification transient is to convert the end-user power factor correction banks to harmonic filters. An inductance in series with the power factor correction bank was used to decrease the transient voltage at the customer bus to acceptable levees. The interception of the impulse from the phase wire is fairly straight forward by properly installed surge arresters. The simulation shows that the addition of the surge arrester at the customer location can achieve a substantial reduction of the transient magnitude.

• 전기의세계
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• 제21권4호
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• pp.15-21
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• 1972

For the conventional DC machine, the armature MMF is negligible compared with field MMF except when the machine is under heavy load or transient conditions. During the motor starting or reversal, the transient armature current and corresponding MMF effect the flux density of each pole in the machine magnetic circuit. However, the circuit flux density is restored to normal values by the field winding MMF after the transient armature current dies in an electromagnetic DC motor. Permanent magnet servomotor have no field windings about the circuit poles to restore circuit flux density through the demagnetized part of each pole after the transient armature MMF dies, and portions of the magnetic circuit stay permanently demagnetized. Thus the problem of stabilizing a magnet pole piece under the influence of the transient armature current need attentions. This work present the recoil operation of the servomotor with PM poles in conjunctions with the influence of the armature reaction effect. The development of an analytical and quantatative study is presented for predicting the regime of the recoil operation under this condition.

• 조명전기설비학회논문지
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• 제14권6호
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• pp.18-25
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• 2000

본 논문에서는 과도전압과 전원선 방해파로부터 가전기기틀 안전하게 보호할 수 있는 전자파 대용 단위세대 분전반의 설계 및 제작에 대하에 기술하였다. 제안한 분전반은 바리스터, 캐패시터 및 간선도채의 인덕턴스로 구성한 과도전업 차단장치와 전자파 필터를 내장하고 있다. 시제작한 분전반은 IEC 규격의 조합형 서지 발생장치와 회로밍 분석키를 이용하여, 과도전압에 대한차단특성과 전원선 방해파의 감쇠특성을 평가하였다. 실험 결과로부E] 본 연구에서 제안한 분전빈은 IEC 61000-4-5에 규정한 서지내생기준을 만족하였으며, 150[kHz]-30[MHz] 대역의 전원선 방해파에 대해 20[dB] 이상의 감소효과를 나타내었다.

• 한국전자파학회논문지
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• 제24권8호
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• pp.860-872
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• 2013

본 논문은 국내외 재난통신망 구축 현황과 기술 발전을 조사 분석하여 합리적이고 효율적인 재난통신망 구축 방안을 제시한다. 연구한 결과, 우리나라는 TRS 기반의 재난통신망이 전국 규모로 구축되어 있지 못한 상황에서 완전 재난통신 광대역 자가망으로 진화하기 위해서는 5년 이상의 과도기적인 재난통신망 구축 및 운영이 불가피하다. 따라서 광대역 이동 통신 기술 기반의 자가망을 구축하면서 이 기술이 성숙될 때까지 상용 TRS와 상용 모바일 광대역망을 보완 활용하는 것이 필요하며, 이를 구체적으로 설계하고 검증하기 위한 전담 조직의 설립이 적극적으로 검토될 필요가 있다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.927-932
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• 2001

It is intended to develope an algorithm for dynamic simulation of fast-acting solenoid valves. The coupled equations of the electric, magnetic, and mechanical systems should be solved simultaneously in a transient nonlinear manner. The transient nonlinear electromagnetic field is analyzed by the Finite Element Method (FEM), which is coupled with nonlinear electronic circuitry. The dynamic movement of the solenoid valve is analyzed at every time step from the force balances acting on the plunger, which include the electromagnetic force calculated from the Finite Element analysis as well as the elastic force by a spring and the hydrodynamic pressure force along the flow passage. Dynamic responses of the solenoid valves predicted by this algorithm agree well with the experimental results including bouncing effects.