Technical Information
System Requirements
SMA Solar Technology AG
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4 System Requirements
The system requirements that are required for operating a GFDI are described below:
• The PV generator is centrally grounded in the Sunny Central. Additional grounding within the system is not
permissible.
• Both poles must be installed with protection against short-circuits and ground faults.
• Cable protection fuses should only be located in the pole that is not grounded.
• It should be possible to disconnect the grounded pole using disconnectors or isolating blades to take
measurements under load-free conditions.
• Both poles are live potentials and must be protected against direct contact.
5 Modifications to the Standard Inverter
The modifications performed to the Sunny Central equipped with the "GFDI" option will be described below in
comparison with the standard inverters.
• The inverter is no longer equipped with insulation monitoring.
• The PV generator is centrally grounded in the Sunny Central by the GFDI.
• The grounded pole is installed on an insulated busbar.
• The cable protection fuses are only located in the pole that is not grounded.
• The grounded pole can be disconnected using isolating blades, thus allowing work to be performed on
the device or measurements to be taken under load-free conditions.
• The "R-Iso" spot value is no longer available as a measurement value, but it is still displayed in the "Other"
menu.
