SMA SC 400HE - Manual (Page 23)

SMA Solar Technology AG 3 Product Description
Operating Manual SC4-63HE-BE-BEN103280 23
Figure 8: GFDI in the Sunny Central
Ground fault on ungrounded pole
If a ground fault occurs at the PV array pole that is not grounded, the residual current flows through
the GFDI and back to the grounded pole, thus tripping the GFDI. This interrupts the residual current
and the PV array is not grounded via the ground fault.
If the GFDI is tripped, the monitoring device switches off the inverter and the insulation error needs to
be corrected.
Ground fault on grounded pole
The GFDI is bypassed when a ground fault occurs in the grounded pole of the PV array. The ground
fault on the grounded pole cannot be reliably detected. If the Sunny Central is equipped with an
additional insulation monitoring device, this type of error will be detected.
3.8.3 Remote GFDI
Depending on the order, the insulation monitoring in the Sunny Central is carried out via a ground
fault detection interruption with a remote tripped, abbreviated "remote GFDI". This process is used to
ground one pole of the PV array. Remote GFDI also enables automatic error processing. This prevents
downtimes and service calls due to temporary insulation errors, such as condensation on the modules.
A high-performance miniature circuit-breaker with adjustable trip current with K characteristics is used
as a remote GFDI. It is integrated in the inverter and connected between an input busbar and the
protective conductor bar.
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