High capacity arrester makes use of gliding spark gap technology
October 2001
Electrical Power & Protection
The Dehnventil from Surge Technology is a two or four-pole arrester incorporating patented specialised gliding spark gap technology, which limits overvoltage values to below 3 kV during direct lightning strikes. The spark gap operates in parallel with heavy-duty arresters, which reduce surge voltages caused by direct lightning strikes to below 900 V.
Capable of protecting against direct lightning strikes of 100 kA per pole, the Dehnventil carries the SABS mark of approval and is guaranteed to operate effectively for 10 years. It was the first product to be manufactured locally to comply with the IEC 1024-1-1 standards for lightning current arresters used between Zone 0 (outside a building) and Zone 1 (immediately inside the building).
In the event of a direct lightning strike with multiple partial surges into a low voltage reticulation network, damage to the arrester could be caused by the first partial lightning current, allowing subsequent damaging currents to pass into the building without being limited to safe levels. With the two-step spark-gap/varistor protection, the Dehnventil is suitable for both 220 V and 380 V systems.
In instances where highly frequent discharges or long lasting low amplitude lightning currents are experienced, the characteristics of the varistors may change, allowing unwanted currents to flow at lower voltages. The Dehnventil has been designed to contain a special control disconnection mechanism which, under these conditions, will disconnect the defective varistor and still provide direct lightning surge current protection.
A signal neon lamp indicates the triggered state of the disconnected mechanism Remote indication is also possible and a test button allows the status of the arrester to be checked at any time.
Surge Technology
(011) 792 1303
[email protected]
www.surgetek.co.za
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