PV Cylindrical Fuses

Special demands are made on fuses for application in photovoltaic systems. These fuses have a high DC rated voltage and a tripping characteristic specially designed to protect PV modules and their connecting cables (the newly defined operational class gPV). It is also crucial that the PV fuses do not age in spite of strongly alternating load currents, in order to ensure high plant availability throughout the service life of the PV system. The fuses must also be able to withstand high temperature fluctua- tions without damage. These requirements were only incorpo- rated into an international standard in recent years and have now been published as IEC 60269-6. All Siemens photovoltaic fuse systems comply with this new standard. Furthermore, they also already comply with the re- cently agreed corrections to the characteristic curves, which will be incorporated in the next standard update. The IEC cylindrical fuses used as string fuses also correspond to the characteristic curves specified in UL standard UL 2579.

PV Cumulative Fuses

The PV fuses in LV HRC design are usually used as cumulative fuses upstream of the inverter. In addition, they can also be used for protecting groups (PV subarrays). For the PV cumulative fuses of size 1, standard LV HRC fuse bases are available. For PV cumulative fuses of size 1L, 1XL, 2L, 2XL and 3L, we have de- veloped a special 3NH7...-4 fuse base with a swiveling mecha- nism which combines maximum touch protection with maximum user-friendliness. This makes it possible to change fuses safely and without the need for any tools, such as a fuse handle. This provides safe and fast access even in an emergency.