DSF surge arrestors comply with new and emerging standards for DC-side surge protection in PV systems. In addition, they extend the Carlo Gavazzi product family, with three DSF models taking the maximum nominal voltage up to 1200V DC. Available in two- or three-pole configurations, the devices provide both differential and common-mode protection.
Innovative built-in technologies cater for both long-duration temporary overvoltage and instantaneous surges lasting microseconds. The former is addressed by a path combining a current limiter with varistor, whilst faster events are routed to a path with varistor and gas tube surge arrester.
Their innovative technology protects internal varistors from the leakage current that could damage and age them when the nominal DC voltage of the plant is temporary exceeded – for example in mornings when the solar panels are cold or in the case of wrong connections. When the varistor nears its end of life, DSF technology ensures the arrester is intrinsically safe with regard to short-circuit behaviour.
DSF arrestors are based on removable cartridges, which can be replaced without leaving the installation unprotected. Exhausted cartridges are indicated by a red optical window on the front panel and a voltage-free contact is provided for remote function monitoring. Internal wiring and labelled terminals contribute further to quicker, simpler installation and maintenance.