• Journal of Electrical Engineering and Technology
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• 제13권4호
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• pp.1697-1704
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• 2018

As a key component of lighting location system (LLS) for lightning warning, the atmospheric electric field measuring is required to have high accuracy. The Conventional methods of the existent electric field measurement meter can only detect the vertical component of the atmospheric electric field, which cannot acquire the realistic electric field in the thunderstorm. This paper proposed a three dimensional (3D) electric field system for atmospheric electric field measurement, which is capable of three orthogonal directions in X, Y, Z, measuring. By analyzing the relationship between the electric field and the relative permittivity of ground surface, the permittivity is calculated, and an efficiency 3D measurement model is derived. On this basis, a three-dimensional electric field sensor and a permittivity sensor are adopted to detect the spatial electric field. Moreover, the elevation and azimuth of the detected target are calculated, which reveal the location information of the target. Experimental results show that the proposed 3D electric field meter has satisfactory sensitivity to the three components of electric field. Additionally, several observation results in the fair and thunderstorm weather have been presented.

• 조명전기설비학회논문지
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• 제30권2호
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• pp.78-84
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• 2016

This paper is focused on the measurement and analysis of an atmospheric electric field which is caused by thunderclouds. The electric field due to thunderclouds changes very slowly. For this reason, the extremely low frequency E-field sensor needs to be used for measuring the atmospheric electric field strength. The balloon-carried E-field sensor system with the time constant of 1sec was designed and fabricated. The electric field sensor consists of $100mm{\times}100mm$ copper plate, active integrator, high pass and low pass filters and batteries. The measurements of atmospheric electric fields were made by the balloon-carried E-field sensor and radiosonde, which sends the data back to ground in real time. From the calibration experiments, the response sensitivity of the E-field sensor was 0.154mV/kV/m in the frequency range of less than 1kHz. As a result from the actual experiment of the atmospheric electric field, the electric field signals were observed from the altitude of about 2.5km. Also, as the altitude was increased, the detected electric field wave oscillated with the fluctuation of sensing plate. The proposed method seems suitable for measurements of atmospheric electric fields, because it is inexpensive, simple to use and launch.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 A
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• pp.351-353
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• 1999

In this paper, electric field analysis of 170kV class GCB is carried out. Considering the movement of arcing contacts during circuit interruption, electric field analysis between moving and fixed contacts is performed with changing the stroke length. From analysis results, electric field stresses are high at stationary arcing contact, moving arcing contact and varies at changing nozzle shapes. Specially, the stationary arcing contact shape has an significant effect on the capacitive small current interruption and the reduction of the electric field stress at this area is important. Varying the shape of stationary arcing contact, electric field analysis is carried out and the optimal shpae of the fixed arcing contact where the electric field stress is low is designed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.847-849
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• 1996

As the power demands increases, one of the most important data is inside electric field of equipment in designing of insulators ami insulated wire for EHV distribution line. So far finite element analysis method is widely used to calculate this electric field. However as the shape of insulator becomes complicated, it is difficult in producing the mesh which suitable the shape. Especially, we have many difficulty that produce dense fine mesh only where the electric field is concentrated. Therefore in this paper, we perform the each conditional analysis of electric field using the Maxwell 3D Simulator to recover this defects. And we try to analyze electric field through the conventional 2 dimensional and 3 dimensional analysis in case of salt contamination on the surface of a insulator.

• 한국대기환경학회지
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• 제12권3호
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• pp.243-254
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• 1996

The main purpose of this study is to investigate the collection efficiency characteristics of a cylindrical ESP. To do that, it is necessary to analyze the electric field, gas flow field, and mechanism of particle movement by numerical simulation based on EHD model. For a gas flow field, Navier-Stokes equation involving the electric source term was solved by SIMPLE algorithm. In case of the electric field, the current continuity and electric field equations were solved by S.O.R. method. The analysis of particle movement was performed on the basis of PSI-CELL model from the Lagrangian viewpoint. The results showed that the influence on the gas flow field by the electric field is almost negligible in a cylindrical ESP. The particle drift velocity $V_P$ toward the collection surface is increased continuously by the electrostatic force due to the rise of particle charge as the particle is moving to the flow direction and the particle size becomes larger. The collection efficiency is to quitely higher with the increase of applied voltage for the same particle size, while becomes smaller as the inlet velocity is increased.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 A
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• pp.21-23
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• 1999

In this paper, the analysis of the electric field in the chamber of high voltage $SF_6$ GCB(Gas Circuit Breaker) is presented by using C-1 FEM. For this purpose, pre-processing program and post-processing program were developed for axisymmetirc 3 dimensional analysis and the electric field in cylindric chamber was analyzed. Important problem is that electric analysis must be considered coronal due to break-down of $SF_6$ when it is cutted off. To solve this problem, a procedure is needed to verify that the solution of Poisson's equation for scalar potential satisfy charge continuos condition because of using first order element os not satisfy the electric continuous condition, C-1 FEM is introduce to obtain electirc potential and electric field at the same time. Analysis of the distribution of electric field on model was done. It is confirmed that the developed program in this paper applicable to design and to analyze of characteristics in total program as electric characteristics analysis routine.

• 전자공학회논문지A
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• 제33A권7호
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• pp.99-110
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• 1996

In this paper, the analysis o fthe electric field distribution for TEM cell which is matched iwth 50 is performed, and the relations of variables for characteristic impedance are derived. Quasi-static approximations are used to calculate the fiedl strength of the internal field of TEM cell. The results of the improved method for analysis of the electric field is compared with that of R.J. Spigel. and the improved method for characteristic impedance and the results of numerical analysis are shown.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2005년도 학술대회 논문집
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• pp.281-284
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• 2005

This paper deals with the parametric analysis of electric and magnetic fields generated by lightning discharges. The measuring system consisted of the plate-type electric field and loop-type magnetic field sensor, the voltage follower, the active integrator and LabVIEW software. The parameters of the electric and magnetic field waveforms produced by intracloud lightning strokes were presented.

• Applied Microscopy
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• 제36권spc1호
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• pp.63-69
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• 2006

By utilizing a field emission gun and a biprism installed on a transmission electron microscope (TEM), electron holography is extensively carried out to visualize the electric and magnetic fields of nanomaterials. In the electric field analysis, the distribution of electric potential in a sharp tip made of W coated with $ZrO_2$ is visualized by applying the voltage to the tip. Denser contour lines due to the electric potential are observed with an increase in the bias voltage. In the magnetic field analysis by producing the strong magnetic field with a sharp magnetic needle made of a permanent magnet, the in situ experiment is carried out to investigate the magnetization of hard magnetic materials. The results of these experiments clearly demonstrate that electron holography is a promising advanced transmission electron microscopy technique to characterize the electric and magnetic properties of nanomaterials.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2164-2166
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• 1999

This paper is describes the measured electric field waveform radiated by lightning discharge. We have performed measurement and analysis of the electric fields associated with stepped leaders. Electric field measurement system was composed of hemisphere electric field sensor, measurement system of a distance from lightning strokes, automatical recording system, A/D board, personal computer etc. A/D board have high sampling time, high speed data processing, 8bit of resolution. Also, measured characteristics of stepped leaders radiated by were analyzed.