Delta RPI M50A_120 - Use with Solar Modules that Have to be Grounded

5 Planning the installation
Installation and Operation Manual for RPI M50A
28
5.8.3 Use with solar modules that have to be
grounded.
NOTICE
Machine and equipment damage
may occur.
► When the DC inputs are grounded,
all of the strings must be connected
in parallel and then connected to
the inverters.
► Additionally, an external isolation
transformer must be installed on
the AC side, otherwise, damage will
result and the inverter will not work
properly.
When the DC inputs are grounded, all of the strings
must be connected in parallel and then connected to
the inverter(s).
When the solar modules need to be grounded, an
external isolation transformer has to be implemented
to the AC side of the PV system as shown in Fig.
5.16, p. 28.
Depending on the DC connection type, different set-
tings for insulation detection are needed, see “8.7
Insulation mode and insulation resistance”, p. 59.
You have to prepare the inverter for use with
grounded solar modules, see Fig. 5.17, p. 29 and
Fig. 5.18, p. 30. Because you have to remove the
cover of the fuse section, you should do this before
you hang the inverter on the wall and do it in a dry
environment. For a detailed description how to do
this, see “6.5 Connecting to the solar modules (DC)”,
p. 42.
OFF
ON
DISCONN.
AC/DC
AC OUTPUT DC INPUT
DC 1 DC 2
COMM.
+– +– +– +–
1 - L1
2 - L2
3 - L3
4 - N
5 - PE
1 - L1
2 - L2
3 - L3
- PE
Distribution Box
Parallel DC inputs only
AC wiring
DC wiring
3P3W 3P4W
PV array
Utility
3-phase, 230/400 V
AC
star or delta connection
Inverter
230/400 V
AC
Isolated
transformer
Z
Z
+
–
Positive grounding
Negative grounding
Fig. 5.16: System design with positive or negative grounding of the solar modules