Aleksić, Slavoljub R.

Ilic, Saša S.

Digitale Bibliothek Thüringen

  PROCEEDINGS 11-15 September 2006      FACULTY OF ELECTRICAL ENGINEERING AND INFORMATION SCIENCE    INFORMATION TECHNOLOGY AND ELECTRICAL ENGINEERING - DEVICES AND SYSTEMS, MATERIALS AND TECHNOLOGIES FOR THE FUTURE      Startseite / Index: http://www.db-thueringen.de/servlets/DocumentServlet?id=12391 51. IWK Internationales Wissenschaftliches Kolloquium International Scientific Colloquium Impressum  Herausgeber: Der Rektor der Technischen Universität llmenau  Univ.-Prof. Dr. rer. nat. habil. Peter Scharff  Redaktion: Referat Marketing und Studentische Angelegenheiten  Andrea Schneider   Fakultät für Elektrotechnik und Informationstechnik  Susanne Jakob  Dipl.-Ing. Helge Drumm  Redaktionsschluss: 07. Juli 2006  Technische Realisierung (CD-Rom-Ausgabe):  Institut für Medientechnik an der TU Ilmenau  Dipl.-Ing. Christian Weigel  Dipl.-Ing. Marco Albrecht  Dipl.-Ing. Helge Drumm  Technische Realisierung (Online-Ausgabe):  Universitätsbibliothek Ilmenau    Postfach 10 05 65  98684 Ilmenau  Verlag:   Verlag ISLE, Betriebsstätte des ISLE e.V.  Werner-von-Siemens-Str. 16  98693 llrnenau   © Technische Universität llmenau (Thür.) 2006  Diese Publikationen und alle in ihr enthaltenen Beiträge und Abbildungen sind urheberrechtlich geschützt. Mit Ausnahme der gesetzlich zugelassenen Fälle ist eine Verwertung ohne Einwilligung der Redaktion strafbar.   ISBN (Druckausgabe): 3-938843-15-2 ISBN (CD-Rom-Ausgabe): 3-938843-16-0  Startseite / Index: http://www.db-thueringen.de/servlets/DocumentServlet?id=12391  51st Internationales Wissenschaftliches Kolloquium Technische Universität Ilmenau  September 11 – 15, 2006   Field Distribution and Effective Height of Lightning Protection Rod with Horizontal Circular Loop – Full Model  Saša S. ILIĆ and Slavoljub R. ALEKSIĆ  1. INTRODUCTION  During a sunny summer day atmospheric electric field strength is in our region around mV150 , increasing during a thunderstorm till enormous values of around mkV10mkV5 ÷ . Such an atmospheric field is practically constant in time and almost homogeneous at long distances from the earth surface. Existing objects and buildings per-turb the atmospheric field, so the field distribution in urban regions is non-homogeneous and very complex.  The atmospheric field distribution around the lightning protection rod with circular loop (Fig. 1) will be prese-nted in this paper. Based on  obtained results it is possible to determine the strength of resulting electric field in the surroundings of an isolated lightning protection rod with horizontal circular loop and to construct equipotential and equienergetic contours. It is also possible to determine the effective height of the lightning protection rod installed at earth surface and to investigate the influence of  the volume and shape on effective height of lightning protection rod with horizontal loop [1]. These investigations are significant because the vertical rod in galvanic connection with horizontal loop has become the Serbian standard of  lightning protection, JUS N. B4. 811. The theoretical basis of vertical rod with horizontal loop as lightning protection system has been for the first time presented in 1988 at light-ning protection conference in Graz [1]. At the next conference on lightning protection, in 1992, in Berlin [2], the group of Japanese explorers has experimentally confirmed the mentioned theoretical results. The experimetally results will be presented here too. In papers published up to now [3-13], all the parts of lightning protection rod with horizontal circular loop haven’t been considered, that are otherwise used for fixing this lightning rod.  E0PECABChlll02rsHNational standard: JUS N. B4. 811E0ABCPECJUS N. B4. 8112a2adα  Fig. 1. Lightning protection rod with horizontal circular loop (JUS N. B4. 811).  2. THEORETICAL APPROACH  In order to determine electric field and potential distribution in the surroundings of  the  lightning protection rod with horizontal circular loop in atmospheric electric filed, point matching method and metod of segments are used.  So the whole system is replaced by point equivalent  unknown charges with position in centres of small segments. The upper rod basis is replaced by small spherical equivalent electrode having radius π= 0e 2ra , where 0r  is radius of lightning protection rod. Finally, using image theorem, the potential in the field point ( )zyx ,,M  can be given in the following form  ( ) ( ) ( ) ( ) ( ) ( )∑= ⎟⎟⎟⎠⎞⎜⎜⎜⎝⎛++−+−−−+−+−πε+−=ϕNn nnnnnnnzzyyxxzzyyxxQzE122222200114   (1) where: 0E  is intensity of atmospheric electric field; and nQ  are charges and nnn zyx ,,  coordinates of the positions of the point charges.   Boundary condition that the potential of all parts of this lightning protection rod is equal to zero is applied to equation (1). This equation can be solved numerically using point matching method, so the linear equations system is formed. After solving this system the unknowns can be determined and the necessary calculation can be performed in the standard way. So the  electrical dipole moment can be written as  ∑==Nnnn zQp1u 2 .                                                                           (2) In case of half spherical body of radius La  at the earth surface, the electrical dipole moment is  .4 03L0L Eap πε=                                                                               (3) The dipole moment of the single vertical thin rod, having circular cross- section of radius eff0r  and height effH , and placed in axial atmospheric electric field, is ( )eff0eff03eff0s 2ln34rHEHp πε= .                                                                   (4) After equalizing (2) and (3) i. e. (4), using the condition eff0eff0 rHrH = , effective height of equivalent Franclin’s rod can be obtained (Fig. 2).  E00PECABChlll02rsHH = h6 m,  = 5.6 m,s = l4 m,  = 5.64 m,d = r  1.05 m,  = 3 cm,a = 1.5 cmReal dimensions:JUS N. B4. 811E0PEC< = >0eff2reffHFranklin’s rod  Fig. 2. Equivalent Franklin’s rod.  3. NUMERICAL RESULTS  All results for field distribution and effective height are presented graphically.    a)   b)   c)  Fig. 3. Field distribution near lightning protection rod (JUS N. B4. 811)  versus different parameter α .  0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.001.051.101.151.201.251.301.351.401.451.50   d/H = 0.125  d/H = 0.175  d/H = 0.225  d/H = 0.275Heff /Hh/H  a) 0.075 0.100 0.125 0.150 0.175 0.200 0.225 0.2501.051.101.151.201.251.301.351.401.45   h/H = 0.666  h/H = 0.766  h/H = 0.866  h/H = 0.966Heff /Hd/H  b)  Fig. 4. Effective height of lightning protection rod (JUS N. B4. 811) versus parameters Hh and Hd .    4. CONCLUSION  Theoretical research has a numerical background and the results for electric field distribution and effective height are presented graphically. Effective height for real dimensions of lightning protection rod with horizontal circular loop has value HH 3.1eff = . Effective height is one very important parameter for defining protection zone versus protection level of proposed lightning protection rod. The rod is tested in high voltage laboratory (Japan), and experimental results for effective height have very good agreement with theoretically obtained results.      Fig. 5. Photos of installed lightning protection rod (JUS N. B4. 811).  References:     [1] Dragutin M. Veličković, One Proposal for Effective Construction of Lightning Protection Rods, Paper distributed at 19th International Conference of Lightning Protection, Graz, Austria, September 1988.  [2] Y. Nagai, S. Nishigama, G. Ikeda, Experiment of Lightning Protection Rod, 21st International Conference on Lightning Protection, Berlin, Germany, September 1992.   [3] Dragutin M. Veličković, Ilić S. Saša, Efektivne visine štapnih hvataljki, treća međunarodna konferencija “Rizik tehnoloških sistema i životna sredina” , str. 95-98, Fakultet zaštite na radu, 30-31 Oktobar, Niš, 1997. (in serbian)  [4] Dragutin M. Veličković, Saša S. Ilić, Atmospheric Electric Field Distribution in the Surroundings of Buildings with Lightning Protection Rods, International Conference on Applied and Theoretical Electricity - ICATE ’98, Vol.1, pp. 41-46, 4-6 June 1998, Craiova, Romania.  [5] Dragutin M. Veličković, Saša S. Ilić, Electric Field and Potential in surroundings of Lightning Protection Rod with Coaxial Circular Loop, 1st Conference on Electrical Engineering & Electronics – EE ’98, pp. 31-36, 3-5 December 1998, Gabrovo, Bulgarian.  [6] Dragutin M. Veličković, Saša S. Ilić, Uticaj objekta na raspodelu atmosferskog električnog polja kog gromobranskog štapa sa horizontalnim obručem, Zbornik radova konferencije ETRAN, 20-22 septembar Zlatibor, str. 180-183, 1999. (in serbian)   [7] Dragutin Veličković and Saša Ilić, Distribution of Atmospheric Electric Filed in the Surroundings of Buildings With Lightning protection rods, JOURNAL of ELECTROTHENICS and MATHEMATICS, Vol. 5, No. 1, pp. 47-58, December 2000, Priština.  [8] Dragutin M. Veličković, Saša. S. Ilić, Atmospheric Electric Filed Distribution in Urban Regions, 5th International Conference on Applied Electromagnetics PES 2001, pp. 189-192, 8-10 October, Niš, 2001.  [9] Saša. S. Ilić, Raspodela atmosferskog električnog polja u okolini objekta sa Franklinovim gromobranom i hvataljkom sa kružnim prstenom, Zbornik radova konferencije ATMOSFERSKA PRAŽNJENJA I ZAŠTITA, str. 295-301, 25-26 Oktobar, Vrnjačka Banja, 2001. (in serbian)  [10] Saša S. Ilić, Zgrada paralelopipednog oblika sa ugrađenim Franklinovim gromobranom u zemljinom atmosferskom polju, Zbornik radova konferencije ETRAN, Sveska 2, 4-7 jun, Bukovička Banja, str. 202-205, 2001. (in serbian)  [11] Saša S. Ilić, Atmospheric Electric Field Distribution in the Surroundings of Parallelepiped Buildings With Lightning Protection Rod, Summer School SOZOPOL' 2002, pp. 73-76, 2002.  [12] Dragutin M. Veličković, Saša S. Ilić, Vesna Češelkoska, Alenka Milovanović, Proračun raspodele zemljinog atmosferskog električnog polja u životnoj i radnoj sredini, (invited paper), Zbornik radova konferencije ETRAN, 6-10 jun, Čačak, str. 204-216, 2004. (in serbian)  [13] Dragutin M. Veličković, Saša S. Ilić, Atmospheric Electricn Field Distribution in the Surroundings of Buildings Having Lightning Protection Rods With/Without Circular Loop, 17th International Symposium and Exhibition on Electromagnetic Compatibility EMC2004 (CDROM), Wroclaw, 29 june-01 july, Poland, 2004.    Address of Authors:     Saša S. ILIĆ              Slavoljub R. ALEKSIĆ UNIVERSITY OF NIŠ           UNIVERSITY OF NIŠ Faculty of Electrical Engineering         Faculty of Electrical Engineering Aleksandra Medvedeva 14          Aleksandra Medvedeva 14 18000 Niš             18000 Niš Serbia              Serbia Phone: +381 64 4332134          Phone: +381 18 529430 Fax:     +381 18 588 399           Fax:     +381 18 588 399 E-mail: silic@elfak.ni.ac.yu          E-mail: as@elfak.ni.ac.yu 

Field distribution and effective height of lightning protection rod with horizontal circular loop – full model

https://www.db-thueringen.de/servlets/MCRFileNodeServlet/dbt_derivate_00017697/IWK_2006_3_3_10.pdf

Field distribution and effective height of lightning protection rod with horizontal circular loop – full model

Abstract

Similar works

Full text

Available Versions

Digitale Bibliothek Thüringen