Advanced circuit interruption now extended to the area of Type 1 arresters .
Digitalisation, networked systems and automation are rendering modern electrical installations increasingly complex. The rising number of renewable energy sources in the grid is changing its parameters regarding short-circuit behaviour and protection technology, creating fresh challenges for planners and installers. With the launch of our new DEHNventil ACI M TNS 264 FM, DEHN is now the first supplier to launch an arrester for Type 1 applications based on its ACI (Advanced Circuit Interruption) technology. The specialist for surge and lightning protection as well as safety equipment is thus expanding its established ACI portfolio for Type 2 arresters to create a comprehensive product family which fulfils the increasingly stringent requirements on surge protection in the field of electrical installation and planning.
Conventional overcurrent protection such as fuses or circuit breakers is only suitable in a limited capacity for protecting surge protective devices (SPDs), as made clear by BS 7671 – 18th edition, as they can trigger unintentionally when exposed to lightning or impulse currents. The maximum backup fuse specified for the SPD does not reliably protect against residual currents in the range of several tens or hundreds of amperes, which can lead to thermal overload. By introducing the innovative ACI technology here, DEHN is pursuing a completely new approach. The classic overcurrent protection concept is replaced by integrating a powerful switch/spark gap combination directly into the surge protective device. In addition to offering overcurrent protection, this provides galvanic isolation in normal conditions, resulting in no leakage currents and a significant increase in the resistance to mains frequency temporary overvoltage (TOV). This technology offers numerous advantages for planners and installers, reducing the planning effort without
compromising operational safety. Dimensioning errors, questions about selectivity and complex calculations are now a thing of the past.
Reliable protection on the feed-in side
Besides setting standards in the Type 2 and DC areas, ACI technology is also of central importance for protection on the feed-in side, especially for Type 1 lightning current arresters. This is where high short-circuit currents and complex network conditions come together. It’s required that surge protection be installed as close as possible to the feeding point of the system, however in practice this is often difficult because connection cables may not be longer than 0.5 metres in order to prevent inductive voltage drops. The modular combined arrester (Type 1+2+3) DEHNventil ACI M TNS 264 FM facilitates implementation: The integrated ACI technology eliminates the need for arrester backup fuses. The device can be mounted directly on earthed DIN rails or earthing rails. A cross sectional area of 16 mm² Cu is always sufficient, since, even in the event of a fault, the integral current is so low that the connection cable is not thermally overloaded. The disconnection function allows the module to be replaced safely during operation, either from the side or from the front, using insulated tools.
Technical details can be found here
For safe and standard-compliant surge protection without a backup fuse: The prewired DEHNventil ACI M TNS 264 FM combined arrester (Type 1 + 2 + 3) provides safety at the supply point of the low-voltage switchgear Image: DEHN SE