SMA SUNNY ISLAND 6.0H - 3 Functions and Design; Design of a Multicluster-Box

3 Functions and Design
SMA Solar Technology AG
System DescriptionSI44M-80H-13-MC-IA-en-1014
3 Functions and Design
3.1 Design of a Multicluster-Box
5
3
MULTICLUSTER-BOX
GRID-CONNECT-
BOX
5
5
5
5
3 3
3
3 3
3
PV INVERTER
GENERATOR
LOADS
DC--
Communication
5-wire cable
DC+
3-wire cable
Extension Cluster
Main Cluster
UTILITY
GRID
optional
Figure 1: Principle of a multicluster system with Multicluster-Box and Grid-Connect-Box
The Multicluster-Box is the main AC distribution board in a multicluster system. The multicluster system forms an AC grid
and is made up of several three-phase clusters. Three Sunny Island inverters are connected in parallel on the DC side
of each cluster. The multicluster system can be set up as an off-grid system or as a system with increased self-
consumption and battery-backup function.
The maincluster is the leading cluster in the multicluster system. The extensionclusters are subordinate to the
maincluster.
PV arrays used as an external energy source must be connected only to the Multicluster-Box. To connect the utility grid
to the multicluster system, a Grid-Connect-Box must be installed.