DC String Protection

String protection makes sense if the PV system has 3 or more strings and can be made with a DC fuse disconnector or a DC string circuit breaker. In addition to fuses, protection of photovoltaic strings is provided by string circuit-breakers. String protection devices protect photovoltaic modules from fault currents. They prevent reverse currents from intact modules to modules with a short circuit. The advantage of string circuit breakers, in comparison to fuses, is that they are immediately ready for use after a trip, when the cause of the trip has been remedied. Eaton offers both fuse-switch disconnectors as well as string circuit-breakers. String protective devices are not enclosed and are intended for installation in customized array junction boxes. When necessary, they can be combined with other components such as side-by-side terminals or surge protective devices. The trip currents for the string circuit breaker can be set over a wide range.