Sunny Island
Installation & Operating Instructions
BWRI33-12:EE
- 124 -
SMA Regelsysteme GmbH
13.2 Single-Phase PV Island Grid without Generator
In an island grid only consisting of power sources based on renewable energy
optimum battery management can only be guaranteed if combined with load man-
agement. This is due to the fact that energy yield may vary strongly depending on
the season. The Sunny Island is optimized for integration of grid-tied PV plants into
an island grid and allows sophisticated load management. The Sunny Boy inverters
available in different sizes can be modularly integrated into the island grid. The Sun-
ny Boys and the Sunny Island communicate via the COM2 interface (RS485). Via
this interface the Sunny Island derates the output power of the Sunny Boys in case
the battery is about to be overcharged.
Disconnection of consumers
In an island grid that does not include a feeder available any time (combustion ag-
gregate) the consumers connected should be classified in terms of which battery
states have to be reached for the Sunny Island to switch them off or - if required -
switch them on. This allows a careful operation of the battery and a high reliability of
the most important consumers. Any consumers in the island grid whose temporary
switch-off will not have serious consequences (such as air conditioning) should be
used in order to reduce consumption within the island grid in case of a low battery.
The Sunny Island should disconnect these consumers via one of the freely configur-
able relays (K1 to K8) if e. g. the battery state N3 or N4 is reached. When battery
state L2 is reached all consumers – if possible - should be switched off at the latest.
A model for wiring is shown in chapter 3.4.10.
