Division for Electricity and Lightning Research, Uppsala University
Postal address: Division for Electricity and Lightning Research,
Box 534, SE-751 21 Uppsala, Sweden Visiting address: Avdelningen för elektricitetslära, the Ångström Laboratory, Lägerhyddsvägen 1 (Polacksbacken, about 2 km south downtown Uppsala) Fax: +46 (0)18 471 58 10 Web page:http://www.el.angstrom.uu.se/
Contact person: Professor Vernon Cooray, phone: +46 (0)18 471 58 09
Research connected to South Asia
Prof. Cooray is working on research connected to atmospheric discharges and lightning. His research group at Uppsala University has initiated a collaboration with scientists from three South Asian educational institutes, namely, the University of Colombo (UC), and the University of Peradeniya (UP), both in Sri Lanka, and the prestigeous Indian Institute of Science (IISc) in Bangalore, India. The research will be specialized on lightning and electrical transients in tropical environments, in order to facilitate postgraduate education and strengthen the research activities related to the lightning and its effects, with power and telecommunication systems as the target. Both India and Sri Lanka are countries located in the tropical regions with high thunderstorm activity and this gives an excellent opportunity to carry out all the required field measurements with real lightning strikes. Also both UU and IISc have excellent high voltage laboratory facilities for testing of equipments and protection devices using lightning voltage and current sources representative of real lightning.
In October 2007, Prof. Cooray received SEK 450 000 as a three-years grant (2008-10) from the Swedish Research Links programme (funded by Sida and the Swedish Research Council)
for this South Asia related project titled ”A collaborative research and education program between Sweden, India and Sri Lanka on the effects of tropical lightning flashes on power and telecommunication systems”. More information on the Swedish
Research Links grants 2007. Project abstract: An industrial country such as Germany spends several million Euros each year on damages caused by lightning flashes. This information when combined with the fact that most of the global lightning activity takes place in the tropics provides insights as to the extent of lightning related problems that a developing nation located in the tropics has to experience. In the tropics lightning is the main source of disturbances in power, telecommunication and computer networks. This pollution of power and telecommunication systems by lightning is a major hindrance to the establishment of advanced industrial processes in developing countries located in the tropical belt. This is the case since power quality goes hand in hand with the quality of industrial products and the cost of production. There is a strong need today to study the influence of tropical lightning environment on the power and telecommunication systems and come up with procedures to mitigate these effects. During lightning strikes, depending upon the intensity or energy associated with the strokes, those equipments responsible for the normal operations suffer damage. The damage could be either critical (wherein the equipment is destroyed and needs replacement) or temporary (wherein the equipment owing to its robustness retains strength again for normal operation). However, the result is loss of equipment, interruption time delays and associated costs.
To overcome the above problem, an appropriate lightning protection for the power and telecommunication equipments have to be envisaged. For this, first a better understanding of the lightning source (physics of lightning and its occurrences) and lightning electromagnetic environment (evaluation and characterisation of lightning currents, electric and magnetic fields due to lightning strikes) are to be known. By knowing the source systematic and realistic theoretical modelling and testing can be carried out with equipments of power and telecommunication systems. By doing so, the failure modes, of those equipments will be well understood and at the same time gives us the key to effective lightning protection. Typical lightning protection design involves the use of lightning interception systems, ground systems, insulators, surge protective devices, etc., and the effectiveness of these devices should be complimented by experiments and theoretical modelling. These devices primarily has two important tasks, first to stop the lightning transients (currents or voltages) entering the equipments and secondly to divert those transients safely to the ground where it is dissipated. The study therefore involves investigations and understanding on two main subjects’ namely lightning physics and effects and also on lightning protection.