3 Product Description
SMA Solar Technology AG
26
SCCP-JP-BA-A4-en-12
User Manual
Type of insulation monitoring device used
The insulation monitoring device used is the A-ISOMETER iso-PV1685 device supplied by Bender GmbH & Co. KG.
3.7.4 Combined Insulation and Ground-Fault Monitoring
3.7.4.1 GFDI and Insulation Monitoring Device
With the order option "GFDI and Insulation Monitoring", it is possible to temporarily disable the PV array grounding and
to check the insulation via the integrated insulation monitoring device.
When the GFDI is closed, the PV array is grounded. In this state, the insulation resistance cannot be determined.
When the GFDI is open, grounding 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 Sunny Central is in the operating state "Grid monitoring", only
the insulation resistance from the PV array to the Sunny Central will be measured.
Insulation monitoring should be performed in the operating state "MPP load operation" so that all sections of the
PV system are included in the insulation measurement.
Insulation Monitoring
The insulation monitoring device will start measuring once the GFDI is open. The insulation monitoring device will initially
assume that the insulation is poor. If the parameter
IsoErrIgn
is set to
Off
, the Sunny Central will switch off temporarily.
The insulation monitoring device takes approximately five minutes to detect the correct insulation resistance. The value of
the insulation resistance can be read off from the user interface in the instantaneous value
Riso
. If the insulation is intact,
the Sunny Central switches back to the operating state "MPP load operation." Once the insulation monitoring process is
complete, the GFDI should be closed again, thus enabling the PV array to revert to grounded operation.
If after approximately five minutes one of the errors
3501 ‒ Insulation error
,
3504 ‒ Insulation error ignored
,
or
3601 ‒ Warning insulation error
is displayed, the insulation is defective. In this case, a qualified person will need
to check and, if necessary, repair the insulation and then acknowledge the error.
Type of insulation monitoring device used
The insulation monitoring device used is the A-ISOMETER iso-PV1685 device supplied by Bender GmbH & Co. KG.
3.7.4.2 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.
When the Remote GFDI is closed, the PV array is grounded. In this state, the insulation resistance cannot be determined.
If the Remote GFDI triggers, initially a temporary error will be assumed and a motor drive will close the Remote GFDI
after a defined delay. No external switch command is required to close the triggered Remote GFDI. The Sunny Central
will switch back to feed-in operation after a defined delay.
In the default setting of the Sunny Central, the software will attempt to start the Remote GFDI up to three times per day.
If the Remote GFDI triggers on several consecutive days, the software will assume that a permanent insulation error has
occurred, and the Sunny Central will no longer revert to operation. 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 Sunny Central is in the operating state
"Grid monitoring", only the insulation resistance from the PV array to the Sunny Central will be measured.
Insulation monitoring should be performed in the operating state "MPP load operation" so that all sections of the
PV system are included in the insulation measurement.
