ICAE International Commission on Atmospheric Electricity

ICAE 2003 Versailles

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Benjamin Franklin

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Wednesday 11th June



Session D Lightning Protection (poster)

  G. A. Dias, F. V. Sonalio, L. C. F. da Silva, H. L. Blauth, A. Eybert-Berard, and J. Pissolato Fo
Lightning protection of special towers in Amazonia
D. A. Palmer, R. Anderson, G. Houghton, and W. Nelson
Investigation into the Feasibility of Triggering Lightning with High-Pressure Conductive Water Jets
  A. Rousseau and P. Gruet
What is a suitable lightning earth ?
  Y. Zhang and X. Liu
Experiment of Artificially Triggered Lightning to Lightning Rod and Semiconductor Lightning Eliminator
  A. Zeddam, S. Person, C. F. Barbosa, and J. A. Rossi
Experiments with telecommunication lines at the lightning experimental site of cachoeira paulista - Brazil


Lightning protection of special towers in Amazonia

G. A. D. (PUCRS)


da Silva,
L. C. F. (PUCRS)



Pissolato Fo,

Pontifícia Universidade Católica do Rio Grande do Sul
Faculadade Engenharia-Departamento de Engenharia Elétrica
EMCG - EletroMagnetic de Compatibility Group
Av. Ipiranga, 6681 - Prédio 30 - Sala 221
90619-900 - Porto Alegre - RS - Brazil
+55 (51) 3320-3594
+55 (051) 3320-4056


The LBA, Large Scale Biosphere-Atmosphere Experiment in Amazonia, is an international research initiative led by Brazil. It is designed to improve the knowledge about rain forest and the interactions between Amazonia and the Earth system To attemp this, the LBA is measuring several points of earth use in the rain forest, installing an amount of instrumented towers in these points. These towers are equipped with a large number of eletronic equipment such as: sonic anemometer, anemoscope, pluviometer, solar panels, thermometers.

In the beginning of the project the towers were not designed with the right lightning protection and grounding and this cost 220 thousand dollars in damages to the towers equipment.

Considering the amount of money spent and the difficult to reach the region of the project, a serie of studies was implemented, beginning to protect the LBA equipment towers against direct lightning strokes and improving the grounding systems used to discharge the lightning current in these stations. Indeed, were done studies of ElectroMagnetic Compatibility (EMC) to protect the electronic devices when induced and/or conducted voltage is generated in the control cables due to direct stroke in the shielding system of each tower.

In the full paper will be illustrated the damages caused by the strikes on the towers and shown how it was established the protection of the towers, and the equipment, and the studies to the grounding system.

Sonic Anemometer

Damaged Sonic Anemometer

The LBA concise experimental plan, 1996
The LBA homepage :http://lba.cptec.inpe.br/lba/indexi.html


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Investigation into the Feasibility of Triggering Lightning with High-Pressure Conductive Water Jets

Douglas A. Palmer, Robert Anderson, George Houghton, William Nelson
1229 Trieste Dr. San Diego, CA 92107 USA


Preliminary studies and calculations of the feasibility of triggering lightning utilizing high-pressure water jets have been conducted and are reported. In this concept a lightning stroke is triggered by a high-pressure electrically conductive water jet is trained upward from the ground toward a cloud system to create a conducting path through the atmosphere and to induce a lightning discharge or stroke. This is achieved by directing the jet upward from a protected enclosure to induce the collection of charges in the clouds to stream downward through the jet, into the enclosure, and harmlessly into the ground. The conducting water jet channel may reach heights of several hundred meters. By diverting the charges from a cloud system in a known path to a harmless conclusion, other structures or objects may be protected.

The conductive material can comprise, for example, water that is made electrically conductive by a solute of a mild acid or salt. In theory, pressures below a hundred atmospheres would generate a jet several hundred meters high. However, windage, or friction from the atmosphere, and breakup into droplets reduces that distance by a significant amount. In concept the jet will be produced only for a time necessary to generate a conductive ion trail to the desired altitude, and then will be halted. The actual volume of water that is consumed to produce the jet will equal the product of the area of the nozzle and the height of the fountain or plume. This volume could equal as few as several liters. The unit would be triggered by threshold determination on an electric field meter in a manner similar to rocket triggered lightning experiments carried out at Camp Blanding.

Preliminary calculations show that deployable units could be sold for less than the price of an automobile, could operate in almost any weather condition and could yield significant economic advantages over other schemes for triggering lightning. It would also be significantly less risky and costly than rocket triggered lightning for research purposes. Initial laboratory studies have shown: 1) that it is feasible to trigger electrical discharges with water jets with an ion source such as a salt or mild acid; 2) the jet design to achieve significant height for low volume is challenging and must be assisted by using a harmless polymer solution to hold the stream together; 3) height ratios on the order of several thousand nozzle diameters are feasible; 4) environmental hazards, outside of the lightning discharge would be minimal; and 5) it may be not be necessary to have a continuous stream to create an effective conduction channel to initiate a lightning stroke to the apparatus.


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 What is a Suitable Lightning Earth ?

A. Rousseau
APS, 10 Rue Gabriel Péri, 94230 Cachan, France

P. Gruet
INERIS, Parc Technologique Alata BP N°2, 60550 Verneuil-en-Halatte - France


The recent spread of lightning protection systems (LPS) has emphasized the fact that a safety electrical earth is not, in most of the cases, a suitable lightning earth. Lightning is a high frequency phenomenon with frequency content up to 1 MHz. In such a case, a 10 m cable may lead to a 100 kV voltage drop meaning that what is supposed to be connected to earth (roughly assumed to be a 0 volt reference point) is in fact at a very high voltage. This may explain failures encountered in building without LPS or with LPS badly installed.

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Experiment of Artificially Triggered Lightning to Lightning Rod and Semiconductor Lightning Eliminator

Yijun Zhang and Xinsheng Liu
Cold and Arid Regions Environmental & Engineering Research Institute, Chinese Academy of Science, Lanzhou 730000, P. R. China


In the summer of 1998 and 1999, the experiment of triggered lightning aimed at testing and comparing the function of conventional type of lightning rod and so-called Semiconductor Lightning Eliminator (SLE) was conducted in Guangzhou, southern China. Altitude triggering technique was adopted for lightning rod (the height being 3.5m) in which steel wire trailed by rocket connected through nylon wire 100m in length to ground. Total of 5 successfully triggered cases were obtained. Relative luminosity of lightning channel in 3 cases was recorded by high speed (1000 frames per second) video camera. Two triggered lightning flashes struck the rod. Among them one changed channel direction in the horizontal distance of around 14m from vertical to slant towards the rod at the height of 15m above its top, clearly showing the attachment process between lightning rod and downward leader. The SLE was composed of 9 rods and mounted on a 8.5m steel tower. Each rod was made of a special material, each being 5m in length and 35k37; in resistance, and had 4 metal tips with 20cm in length on its top. In order to assure the SLE of being struck by triggered lightning the steel wire trailed by rocket was connected, through a piece of nylon wire 6m in length, to the rod tip of SLE. Eleven meaningful data sets or photographs were obtained and the SLE or some of its rods was struck by triggered lightning in 8 cases; among them main channel of lightning formed in 5 cases. The parallel discharges between two or three SLE rods were observed. Flash over occurred in 5 cases in which main channel formed. The lightning current limitation function of SLE when it was struck by triggered lightning, claimed by its manufacturer, was not observed. Besides optical observation by still camera and high speed video camera, triggered lightning current in the bottom of lightning channel, electrical field change, potential arising on grounding network of SLE when it was struck by triggered lightning and other parameters were simultaneously measured. This paper reports the main results obtained in the experiment.


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Experiments with telecommunication lines at the lightning experimental site of cachoeira paulista - Brazil

Ahmed ZEDDAM, Sylvain PERSON,
France Télécom R&D
2, Avenue P. Marzin, 22307 Lannion Cedex, FRANCE

Celio Fonséca BARBOSA, José Antonio ROSSI
Fundação CPqD, Rodovia Campinas-Mogi Miry, km118,5, 13 088-061 CAMPINAS-SP, BRAZIL


Lightning discharges can reach a telecommunication system by a direct strikes mechanism, coupling through the earth or coupling through electromagnetic fields. In order to protect the telecommunications systems against the effects of lightning discharges, the Study Group 5 of the International Telecommunications Union (ITU-T) produced a Handbook and a set of Series K Recommendations, which contain texts with requirements, methods and procedures in order to protect the equipment, installations and the associated people from the effects of lightning discharges.

Two specific Recommendations deal with the protection of telecommunication lines using metallic symmetric conductors against lightning induced surges and direct lightning discharges.

In order to develop new Recommendations and to upgrade the existing ones, some research activity is being carried out on several subjects, as for example:

  • Shielding effect of metallic cable sheath over the lightning induced surges,
  • Protective effect provided by the installation of Surges Protective Devices along a telecommunication line,
  • Procedures for the protection of radio base stations of mobile telephony against lightning discharges.

Since 2001, Fundação CPqD and France Telecom R&D under a technical partnership, carried out such research activities on telecommunication systems at the International Center for Lightning Research (ICLR) located at INPE in Cachoeira Paulista - Brazil.

Figure 1 shows schematically the experimental line and the reference points. There are two aerial telecommunication cables of 3 km long installed in separated poles along the line from Shelter 1 and Cabinet 2. The separation between the lines of poles is around 6 to 8 meters. The philosophy of the experiment is to consider one cable as a reference and to make the different changes on the other cable. By measuring simultaneously the induced surges on both cables it's possible by comparison to evaluate the shielding effect provided by each configuration.

The final paper will present a description of the line experiment, with the identification of the main points and the characteristics of the components, including the grounding systems, the measuring set up and the lightning characteristics of the region. Finally it will present the main results of the proposed line configurations obtained for natural and triggered lightning.

Figure 1 : Experimental telecommunications line



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