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Analysis on Electric Field Based on Three Dimensional Atmospheric Electric Field Apparatus

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Analysis on Electric Field Based on Three Dimensional Atmospheric Electric Field Apparatus J Electr Eng Technol.2018; 13(4): 1697-1704 ISSN(Print) 1975-0102 http://doi.org/10.5370/JEET.2018.13.4.1697 ISSN(Online) 2093-7423 Analysis on Electric Field Based on Three Dimensional Atmospheric Electric Field Apparatus Hong-yan Xing†, Gui-xian He* and Xin-yuan Ji** Abstract – 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. Keywords: Three dimension electric field, Permittivity sensor, Lightning, Electric field analysis. 1. Introduction cloud, which changes with the clouds changes [8]. So, there will be an existence of horizontal components of Monitoring of the atmosphere electric field is an the electric field other than the vertical component. This essential part of lightning warming [1-2]. In recent years, has been well highlighted in Ref [9-11] and elsewhere. atmospheric electric field measuring plays a more and Therefore, it is important to investigate the 3D electric more important role in many industrial and scientific areas, field components in thundercloud to propose more realistic such as aerospace, meteorological, power grid and so on atmospheric electric field. Up to now, many investigators [3-4]. With the increasing use of electric equipment, the have focused on the research of the horizontal components probability of electric system being destroyed by lightning of the electric field. For example, Kamra et al. [12] electromagnetic pulse increases accordingly. Therefore, developed a spherical electric field meter to measure the lightning detection has been a crucial problem in modern electric field vector at 1m above the ground. And later, society. When the thundercloud is closing, the atmospheric Kamra et al. [13] extended their study on the spherical electric field inside and outside the thundercloud changes field meter with Maxwell’s current density, which can find violently, which can be used to predicted the lightning out the location of charge center and the charge destroy occurrences [5]. The atmospheric electric field measurement in a thunderstorm. Tantisattayakul et al. [14] developed a meter, as a conventional diagnostic tool, has been widely hybrid electric field meter to measure the vertical and used in electric field detecting. horizontal electric fields in thunderstorm. Bateman et al. Many researches have been carried out to find out the [15] discussed the application of the aircraft-based rotating- charge center in a thunderstorm and to determine the vane-style electric field mills in NASA’s Marshall Space structure of lightning by detecting the electric field with Flight Center. The mills were installed in the different field mill type electric field meter, which can only detect the positions of the aircraft, and then Mach et al. [16] calculated vertical electric field [6-7]. However, Due to the complexity the relationship between the electric field measured at the of the electric field in the thunderstorm, the atmospheric aircraft and the external vector eclectic field through a electric field is affected by the charge distribution in the calibration technique. Katsuki et al. [17] focused on the electro-optic probe for three-axis electric field measurement. † Corresponding Author: Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of However, those studies usually have complex fabrication Information Science & Technology, China. ([email protected].) process, big volumes and especially high cost. * Key Laboratory for Aerosol-Cloud-Precipitation of China Meteor- Zheng [18] introduced spatial three dimensional electric ological Administration, Nanjing University of Information Science filed measuring system based on L-band meteorological & Technology, China.([email protected]) ** Nanjing University of Information Science & Technology, China. radar for aerial electric field measurement. [19] reported a Received: September 7, 2017; Accepted: May 18, 2018 3D electric measuring method based on coplanar decoupling 1697 Copyright ⓒ The Korean Institute of Electrical Engineers This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/ licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Analysis on Electric Field Based on Three Dimensional Atmospheric Electric Field Apparatus structure to deal with the issue of coupling in three components of electric field. Wang [20] presented a novel X–Y dual axis sensitive sensor for static electric field measurement, which is capable of two-dimensional electric field sensing. g These scholars further improved the 2D and 3D electric a field measuring instruments from the aspects of materials and structures, which solved the problems of the three- dimensional electric field measurement in the air and the coupling of the electric field components between the Fig. 1. 3D electric field model existing electric field sensors. However, their study did not consider the influence of the dielectric constant on as follows: the measurement of the electric field. Because of the good conductivity of the earth, researchers usually regard EEEE=x + y + z (1) the earth as a conductor. It is considered that the electric field near the ground is perpendicular to the ground surface. 2.2 Method analysis However, in reality, the surface layer of the earth is a complex structure, which composed of different components In order to establish the electric field distribution such as soil, rock, and water. So it has a certain dielectric generated by the net charge in the air, the thunderstorm constant and dielectric properties on the surface layer. The cloud and the earth are regarded as a point charge and an electric field near the ground will be tilted, which result in infinite dielectric plane respectively. According to the a horizontal component. Therefore, neglect its dielectric mirror method theory, it can be assumed that the electric properties when measuring 3D electric fields will affect the field generated by the point charge which is at any point of accuracy of the results. Till now, no such researches relevant the region, is generated by the point charge q and its mirror to 3D electric field meter with permittivity measurement or charge q1. Therefore, the potential distribution j1 of the azimuth information of the thunderstorm detected by electric thunderstorm at the ground observation station can be mills have been reported. The three-dimensional electric obtained by Eq. (2) field sensor adopts the principle of electrostatic induction. Three sets of orthogonal electrostatic induction units are 1 q φ1 = [ arranged on the outside of the sensor, and the three- 2 2 2 4πε1 x+ y +() z - H dimensional electric field is measured by forming a (2) ε- ε q differential signal through the shielding and exposure of - 2 1 1 ] 2 2 2 the three groups of sensing units. ε2+ ε 1 x+ y +() z + H In this paper, in an attempt to attain more realistic atmospheric electric field, considering the influence of the Where e1 is the permittivity of the air; e2 is the permittivity, a 3D electric field system is proposed. The permittivity of the Dielectric; x, y, z represent the permittivity sensor is used in this work. The three electric coordinates of the target thunderstorm; H is the altitude of component of X, Y, Z, axis are measured by this device. the observe-station. In addition, the elevation and azimuth of the target are Then the electric field components of Ex, Ey, Ez will be carried out. calculated by (3)-(5) as follows: ¶φ -qx 2. Principle Analysis of Three Dimensional E =1 ={[x2 + y 2 + ( z - H )2 ]- 3/2 x ¶x4 πε Electric Field Measurement 1 (3) ε- ε -2 1 [()]}x2 + y 2 + z + H 2- 3/2 ε+ ε 2.1 Three dimensional electric field model 2 1 ¶φ1 -qy 2 2 2- 3/2 In this section, the principle of 3D electric field Ey = ={[x + y + ( z - H ) ] ¶y4 πε measurement model in a thunderstorm is presented in Fig. 1 (4) ε- ε 1. As shown in Fig. 1, A, B represent the observation site -2 1 [()]}x2 + y 2 + z + H 2- 3/2 ε+ ε and thunderclouds respectively. a is the azimuth angle of 2 1 the thunderclouds. g represents the elevation angle of the ¶φ1 -q 2 2 2- 3/2 thunderclouds. From Fig. 1, it can be seen that the aerial Ez = ={(z - H )[ x + y + ( z - H ) ] ¶z4 πε electric field E is a three-dimensional vector, which can be 1 (5) ε- ε decomposed into E , E , E three components orthogonally. -2 1 (z + H )[ x2 + y 2 + ( z + H )2 ]- 3/2 } x y z ε+ ε The relationship of the three electric components is given 2 1 1698 │ J Electr Eng Technol.2018; 13(4): 1697-1704 Hong-yan Xing, Gui-xian He and Xin-yuan Ji Fig. 3. Proposed framework of 3D electric field instrument Fig.
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