SMA SI 4548-US - Manual (Page 135)

SMA America, LLC 14 Connecting External Sources
Operating Manual SI4548-6048-US-BE-en-20 135
Failure of a Grid Line Conductor
The failure of a line conductor (e.g. broken fuse) on a slave device is treated as a line conductor
failure. The slave device then disconnects this line conductor. If the line conductor is detected as being
available again, it is reconnected.
The line conductor failure on the master device is treated as a grid failure (see above).
Failure of a Slave
If a slave fails, the system continues to operate using the remaining devices of the cluster.
14.2.9 Limitations and Power Control
The Sunny Island burdens the utility grid at each line conductor with the current defined in parameter
"232.03 GdCurNom". The power that is not directly used by the loads flows into the battery for
charging. At the same time, the limits for the AC charging current limit (parameter
"210.02 InvChrgCurMax") on the Sunny Island and the DC charging current limit (parameter
"222.01 BatChrgCurMax") are active. If the battery voltage reaches the charging voltage target
value, it is also reduced (see Section 13.5 "Charge Control", page 110).
If the current set using the parameter "232.03 GdCurNom" is not sufficient for supplying the loads,
the battery provides support.
14.2.10 Operation Together with PV Inverters and Wind Power
Inverters
Silent mode active
When silent mode is activated, the grid cannot be supported.
The grid may temporarily fail. This way, the voltage supply of the loads will be interrupted for a
short time.
Overload of the Sunny Island through high currents. Destruction of the Sunny Island
If the current via the relay exceeds the maximum permissible current, the Sunny Island disconnects
from the utility grid (relay protection).
• The quantity of PV power installed in the stand-alone grid must never exceed the maximum
quantity allowed by the AC input (see Section (see Section 22 "Technical Data", page 226)).
• The maximum AC power of the connected PV inverters and wind power inverters must not
exceed 7 kW in grid-tie systems.
• Observe the following:
P
AC max
of the wind power inverter = P
AC nom
of the Sunny Island