3 Product Description
SMA Solar Technology AG
22
SCCP-JP-BA-A4-en-12
User Manual
• Ground fault on the grounded terminal
The GFDI is bypassed when a ground fault occurs on the grounded terminal of the PV array. A ground fault on the
grounded terminal cannot be reliably detected. If an undetected ground fault occurs on the grounded terminal,
this will pose a safety risk. A further ground fault occurring on the ungrounded terminal will lead to high residual
currents that cannot be interrupted by the ground-fault monitoring unit.
In Ungrounded PV Arrays
An insulation monitoring device constantly determines the insulation resistance using an active measurement procedure.
As soon as the insulation resistance falls below the warning threshold specified in the insulation monitoring device, an
insulation warning will appear on the touch display. As a result, preventative measures can be taken before errors occur,
e.g., personal hazard due to leakage currents, or system failure. If the insulation resistance falls below the configured
warning threshold, the system may be switched off. Use the parameter
IsoErrIgn
to activate or deactivate the
disconnection process under fault conditions.
3.7.2 Ground-Fault Monitoring in Grounded PV Arrays
3.7.2.1 Ground Fault Detection and Interruption (GFDI)
Depending on the order option, ground-fault monitoring in the Sunny Central can be carried out via ground fault detection
and interruption. This grounds one terminal of the PV array.
GFDI is performed via a K-type circuit breaker with adjustable operating current. The GFDI is integrated in the
Sunny Central and connected between an input busbar and the grounding busbar.
Figure 6: GFDI in the Sunny Central
Information:
In order to ensure the residual current monitoring function in grounded systems, the PV array insulation must be
checked at regular intervals. It is therefore advisable to use an additional insulation monitoring device in
grounded systems. This will enable the insulation to be checked at regular intervals.
Position
Designation
A
GFDI
