Combined lightning current and surge arresters
July 2011
Electrical Power & Protection
DEHN’s modular Red/Line DEHNventil family of combined lightning current and surge arresters offers safety and reliability in compact installations.
The devices achieve lightning equipotential bonding and surge protection all in one stage. Designed according to energy coordination criteria, they allow protection of terminal devices at short distances (<5 m). They have a discharge capacity up to 100 kA (10/350 μs) and there is no tripping of 32 A gL/gG fuses up to 50 kA rms short-circuit currents.
Even for expanded electrical installations, DEHNventil devices provide various application possibilities. Encapsulated creepage discharge spark gaps and the small space requirement enable easy integration into switchgear installations or distribution boards.
An important component is the module releasing button. This fixes the protection module reliably to keep a safe connection to the base part, even with maximum loads. If the protection modules have to be replaced, it releases the module with no need for tools, and allows easy removal. By using the double terminals available for all conductor connections, the surge arresters can be connected in series in a space saving and cost effective way up to nominal currents of 125 A, as preferred by IEC 60364-5-53.
The patented RADAX Flow technology for follow current limitation and extinction allows high availability of the electrical installation. Even for high short-circuit currents up to 50 kA rms, upcoming mains follow currents are reduced in such a way that there is a selectivity to small fuse values. Hence upstream fuses cannot trip due to arising mains flow currents.
The operating state/fault indicator of each protective circuit, which is mechanical and requires no power, instantly shows the operating state of the surge arrester. Apart from the standard visual indicator with green and red marks, the type DEHNventil M FM has a 3-pole terminal for remote signalling. With the remote signalling contact being a floating changeover contact, the remote signal can be used as a break or make contact, according to circuit concept.
For more information contact Paul van As, Surgetek, +27 (0)11 792 1303, [email protected], www.surgetek.co.za
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