SMA SC 400HE - Manual (Page 25)

SMA Solar Technology AG 3 Product Description
Operating Manual SC4-63HE-BE-BEN103280 25
With soft grounding, the insulation is monitored by measuring the voltage between the grounded pole
and PE. To do this, the software analyzes the DC voltage "V
PV
+ to PE" on the positive pole or
"V
PV
‒ to PE" on the negative pole when grounded.
If the amount of voltage measured exceeds a certain threshold, the grounding of the PV array is
disconnected and the residual current is interrupted. This threshold is adjustable.
If a soft grounding error occurs, the insulation should be checked by an electrically skilled person and
repaired if necessary. The insulation protection must be reactivated using the reset button in the
device.
3.8.5 Insulation Monitoring Device
The insulation monitoring device monitors the inverter's insulation resistance. The user can configure
the monitoring to the PV modules used.
Figure 11: Insulation monitoring ISO-PV-3 in the Sunny Central
A measuring circuit and a relay with a changeover contact are integrated in the insulation monitoring
device.
The insulation monitoring device is connected between the PV voltage and the PE conductor. The
measuring circuit closes when an insulation error occurs. If the ALARM1 value falls below a specific
threshold, the measuring circuit trips a warning and LED1 turns on.
The measuring circuit generates a failure message and the inverter switches off when the ALARM2
value falls below a specific threshold. LED2 turns on.
Type of insulation monitoring device used
The insulation monitoring device used is the A-ISOMETER iso-PV device supplied by
Bender GmbH and Co. KG.
Object Description
A Display
B Control buttons
C LEDs
SMA
INFO TEST RESET MENU
U2-F10
INFO TEST RESET MENU
U2-F10
C B
A
SUNNY CENTRAL 630HE