• 조명전기설비학회논문지
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• 제27권1호
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• pp.46-52
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• 2013

The current distribution passing through grounding electrode is required for calculating an impedance of grounding electrode using the electromagnetic field model. In this paper the numerical calculation for currents passing through a grounding electrode as a function of frequency was given. The proposed approach is based on the wire antenna model(AM) in the frequency domain. The Pocklington's equation driven from the wire antenna theory was numerically calculated by the Galerkin's method. The triangle function was applied to both the basis function and the weighting function. The current distribution of a horizontal ground electrode was simulated in MATLAB. Also these results were compared with the data obtained from the CDEGS HIFREQ calculation.

• 조명전기설비학회논문지
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• 제27권12호
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• pp.81-86
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• 2013

An electric potential rise of the grounding electrode developed by the lightning stroke currents should be calculated for the purpose of effective protection of electrical and electronic equipment. In this paper, the electromagnetic model was applied to calculate the harmonic impedance of grounding electrode. Also the empirical equation related to the permittivity and resistivity of soil was used. The lightning current waveforms, which are expressed by the Heidler's equation, were used in order to calculate accurately transient electric potential rises. The transient voltage was obtained by using the simulated harmonic impedance and the lightning current in frequency domain. Finally, the transient voltages of horizontal grounding electrode(10m) under lightning stroke currents were calculated by IFFT(Inverse Fast Fourier Transform).

• 한국통신학회논문지
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• 제18권11호
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• pp.1669-1676
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• 1993

본 논문에서는 도체 상자에 부착된 선형 모노폴(thin-straight monopole) 안테나를 wire-grid방법을 적용하여 안테나 및 도체상자를 모델링하였고, 효율적인 계산을 위해 Pocklington 적분 방정식과 모멘트 방법(Moment Method)을 사용하여, 안테나의 특성 변화를 계산하였다. 안테나 및 모델링된 도체상자에 이용된 기저함수는 PWS(Piecewise Sinusoidal)함수이고, 도체상자의 모서리에 흐르는 전류를 효과적으로 표현하기 위해, 접합기저함수(Junction Basis Function)를 사용하였다. 특히, 모서리의 꼭지점에서 전류의 연속 조건을 만족하기 위해, 접합기저 함수가 중복되도록 하였다. 안테나 및 도체상자에 흐르는 전류분포를 계산하여, 입력 임피던스 및 복사패턴을 구하였고, 기존의 결과 데이터와 비교하였다.

• 조명전기설비학회논문지
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• 제28권2호
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• pp.76-83
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• 2014

This paper deals with the numerical method of calculating the frequency-dependent impedances of grounding electrodes. The proposed electromagnetic field approach is based on the solutions to Maxwell's equations obtained from the method of moment in the frequency domain. In order to evaluate the quality of the proposed simulation method, the frequency-dependent impedances of horizontally-buried ground electrodes were presented. The program for calculating the current distributions and impedances of grounding electrodes was implemented in MATLAB. The grounding impedances of two 10m and 50m long horizontal ground electrodes were measured and simulated in the frequency range from 100Hz to 10MHz for easy analysis and comparison. Also the simulated results were compared with those calculated from a sophisticated computer program CDEGS (HIFREQ module). As a result, the resultant results of frequency-dependent impedances obtained by using the numerical simulation method proposed in this work are in good agreement with experimental data. The validity of the approach techniques was confirmed.

• 전자공학회논문지
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• 제50권3호
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• pp.230-236
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• 2013

본 논문은 대표적인 손실 매질인 대지에 위치한 도체의 입력임피던스를 MATLAB을 이용한 자체 프로그램을 활용하여 계산하고, 그 결과를 나타내었다. 도체의 입력임피던스는 안테나 이론의 전자계 모델에서 유도된 포클링턴방정식에 모멘트법이 적용되어 계산되었다. 결과의 정확도를 높이기 위해서 기저함수와 가중함수가 삼각함수인 켈러킨법을 적용하였다. 대지에 위치한 도체의 영상분은 수정된 영상법을 적용하여 고려하였다. 도체의 전류분포에 대한 자체 제작한 프로그램 결과와 NEC 프로그램의 결과를 비교하여 프로그램의 신뢰성을 확인하였다. 대지에 위치한 도체의 길이가 1 m, 2 m인 경우에 도전율에 따른 임피던스를 주파수에 따라 시뮬레이션 하였다. 실제 대지에 설치된 도체의 입력임피던스와 위상을 측정하고 동일한 조건에서의 시뮬레이션 결과와 비교하였다.