SMA SC 500HE-20 - Manual (Page 24)

3 Product Description SMA Solar Technology AG
24 SCxxxHE-20-BE-BEN111210 Operating Manual
GFDI is performed via a high-performance k-type miniature circuit breaker with adjustable operating
current. It is integrated in the inverter and connected between an input busbar and the protective
conductor bar.
Figure 8: Remote GFDI in the Sunny Central
If the remote GFDI trips, a temporary error is assumed and a motor will close the GFDI after a delay.
The triggered remote GFDI can be closed without an external starting command. The inverter can
switch back to feed-in operation after a delay.
In the default setting, the Sunny Central software will attempt to start the GFDI up to 3 times per day.
If the GFDI is triggered on consecutive days, the software assumes a permanent insulation error and
shuts down the inverter permanently. In this case an electrically qualified person needs to check and,
if necessary, repair the insulation and then confirm the error.
3.5.4 Soft Grounding
Depending on the order, the Sunny Central can also monitor for ground faults via soft grounding. This
process grounds one pole of the PV array through a resistor.
Figure 9: Soft grounding in Sunny Central
If a ground fault occurs on the non-grounded pole of the PV array, the soft grounding resistance will
generate a fault current. The fault current increases the voltage of the grounded pole in relation to the
protective conductor. With soft grounding, the insulation is monitored by measuring the voltage
between the grounded pole and the protective conductor. "U
PV
+ to PE" or "U
PV
‒ to PE" is used to
determine the DC voltage when the grounded pole is positive or negative, respectively.
on on o off off
INFO TEST RESET MENU U2-F10
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SUNNY WEBBOX US BC O M NE TC O M SM AC O M M EM O RY RE PO RT SY ST EM PO W ER
SUNNY CENTRAL
STRING MONITOR CONTROLLER
on on o off off
INFO TEST RESET MENU U2-F10
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