The fully automatic station - construction was started in 1998 and has just been completed - takes advantage of the naturally high frequency of lightning strikes at the transmitter mast of the Austrian Broadcasting Company ORF to take measurements producing new findings for lightning protection.
In addition to direct current measurement at the top of the mast, the electromagnetic field emitted from the lightning tunnel and the voltage inputs in lines and solar panels are measured at the Gaisberg station.
The station uses also a high-speed video camera which records up to 1,000 images per second. On the evening of 14 June 2000, the first shots of three lightning strikes into the tower were taken by this special camera.
Evaluations of data collected between 1992 and 1998 by ALDIS, the Austrian Lightning Detection & Information System, had revealed that the ORF transmitter mast on Gaisberg near Salzburg was hit by 40 to 50 lightning strikes annually – and thus constitutes an ideal object for intensive research.
VERBUND has been sponsoring the Gaisberg project, for which funds amounting to five million ATS (363,000 EUR) have been provided so far, with 3.5 million ATS since 1998. Other ALDIS projects have received a total of 2.5 million ATS from VERBUND since 1991.
"Thus VERBUND continues the path of promoting also basic research now that ALDIS has been established", explains Dr. Herbert Schröfelbauer, Deputy Chairman of the VERBUND Board of Management, who is also responsible for research and environment and the current President of the Austrian Association for Electrical Engineering (OEVE). Other partners of the Gaisberg project are the Carinthian electricity company Kelag and the Austrian Association for Electrical Engineering (OEVE).
Lightning is still the most frequent cause for power failures at all voltage levels. The Gaisberg research station is to provide more detailed information about what happens from the physical standpoint when a lightning strikes. VERBUND, operating an extra-high-voltage grid of 3,600 kilometres’ length, is hoping for an economic optimization of its lightning protection systems.
"The Gaisberg station is unique in Europe these days and on the road to achieve international importance in lightning research," said the lightning expert Dr. Gerhard Diendorfer, who is in charge of the ALDIS lightning location system within the OEVE.
Calculated measurements of lightning can be taken in two ways. In the case of triggering, lightning strikes are triggered artificially by launching small rockets which pull a thin metal wire into the thundercloud. However, since the metal wire vaporizes when the lightning strikes the comparability with natural lightning strikes has been doubted. Exposed towers, like the transmitter mast on Gaisberg, offer an alternative - namely to take measurements directly on lightning.
Comparable measurements are taken only in very few research stations all over the world. The data collected at the Gaisberg station will be evaluated in the framework of a close cooperation with some of the internationally renowned lightning research centres, for example the Lightning Research Laboratory of the University of Florida and Japanese research institutes.
"OEVE-E49, the lightning protection standard specification, effective in Austria at present, will soon be replaced by a European standard (ENV 61024-1), which will involve a few major innovations in the design of lightning protection systems," said Dr. Helmut Stärker, Secretary General of OEVE. For the first time, the size and design of a lightning protection system will have to take into account whether or not the building to be protected is located in an area particularly exposed to lightning – ALDIS findings will be applied directly.
Depending on how much protection an object needs, four different lightning protection classes are provided for. Which one is to be applied for a specific building depends on several factors. The most important factors are: risk of being struck by lightning and thus the local frequency of lightning strikes, type of structure of a building (wooden house or reinforced concrete building), and use of the building (computer centre or warehouse).