Remote Gfdi And Insulation Monitoring Device - SMA SUNNY CENTRAL 500CP XT User Manual

10 Function Description
10.2.3.6 Remote GFDI and Insulation Monitoring Device
With the order option "Remote GFDI and Insulation Monitoring", it is possible to automatically correct errors which
have occurred, to temporarily disable the grounding connection of the PV array and to check the insulation with the
integrated insulation monitoring device.
Figure 23: Remote GFDI and Insulation Monitoring Device
Position
A
B
When the Remote GFDI is closed, the PV array is grounded. In this state, the insulation resistance cannot be
determined. If the Remote GFDI trips, initially a temporary error will be assumed and a motor drive will close the
Remote GFDI after a defined waiting time. No external switch command is required to close the tripped Remote GFDI.
The inverter can switch back to feed-in operation after a waiting time.
In the default setting of the inverter, the software will attempt to start the Remote GFDI up to three times per day.
If the Remote GFDI is tripped on several consecutive days, the software assumes a permanent insulation error and the
inverter will no longer switch back on. In this case, a qualified person will need to check and, if necessary, repair the
insulation and then acknowledge the error.
When the Remote GFDI is open, the grounding connection is disabled. In this state, the insulation monitoring device
continuously measures the insulation resistance. In the operating state "MPP load operation", the insulation resistance
of the entire system, from the PV array to the MV transformer, will be measured. If the inverter is in the operating state
"Grid monitoring", only the insulation resistance from the PV array to the inverter will be measured.
Insulation monitoring should be performed in the operating state "MPP load operation". This will ensure that all parts of
the system are included in the insulation measurement.
Insulation monitoring
To disable the grounding of the PV array, the parameter RemMntSvc must be set to On. This will open the
Remote GFDI by means of a motor drive.
If the Remote GFDI has been opened by a motor drive via the parameter RemMntSvc, the insulation monitoring
device will start measuring after the waiting time defined in parameter IsoMeasDly has elapsed. This allows the
insulation monitoring device to determine the insulation resistance without interrupting feed-in operation. If an insulation
error is present, this will only be taken into account at the end of the waiting time.
Once the insulation monitoring process is complete, the parameter RemMntSvc should be set to Off, thus switching
the PV array into grounded operation.
92 SCCPXT-E7-BA-en-58
Designation
Insulation monitoring device
Remote GFDI
SMA Solar Technology AG
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