SMA SI 4548-US - Manual (Page 117)

SMA America, LLC 14 Connecting External Sources
Operating Manual SI4548-6048-US-BE-en-20 117
14 Connecting External Sources
The Sunny Island supports the integration of external energy sources. Here, a distinction is made
between the integration of a generator and the integration of the utility grid.
Both the generator as well as the utility grid are integrated via the AC2 terminal of the Sunny Island.
A single-phase, a split-phase and a three-phase connection can be established. In the case of
single-phase parallel operation, the transfer relays are operated in parallel, making it possible to use
a correspondingly larger current, which in turn allows for a generator or grid connection with a higher
capacity
The Sunny Island has separate parameters for the utility grid and the generator. This generally allows
both operating modes to be used without making additional adjustments. The parameter settings and
display values distinguish between settings or values which are generator-specific or grid-specific and
settings or values (EXT) common to both grid and generator.
14.1 Generator
The Sunny Island can start or stop a generator depending on load power or battery state of charge.
In this case, diverse limits and times are taken into consideration (see Section 14.1.5 "Automatic
Generator Operation", page 122).
Extended Generator Management
If necessary, the Sunny Island and generator supply loads together. The total of the (nominal) power
of both energy sources is available in the stand-alone grid.
14.1.1 Parallel Connection
In the case of Sunny Island inverters connected in parallel which operate on the same line conductor
and in the same cluster, the internal transfer relay is activated simultaneously. It is thus possible to
multiply the generator current and therefore to connect a larger generator or a higher grid current.
The maximum current in the system is limited to 150 A:
Connecting in a single-phase parallel system
When installing parallel single-phase systems, the connection cables for AC1 and AC2 of all
Sunny Island inverters must have the same wire sizes and cable lengths.
Maximum number of Sunny Island Maximum current
1 Sunny Island 56 A
2 Sunny Island 112 A
3 Sunny Island 150 A