11 Glossary
SMA Solar Technology AG
70
SI80H-BE-BEN120810
Operating Manual
Inverter mode
Operating mode of the off-grid inverter in which the off-grid inverter supplies the stand-alone grid from
the energy in the battery. In this operating mode, the off-grid inverter is primarily responsible for the
control of frequency and voltage in the stand-alone grid.
I-Phase
See Constant current phase
Main cluster
The main cluster is the leading cluster within a Multicluster system. The master of the main cluster is the
central user interface for the main cluster and all extension clusters of a stand-alone grid. The master
of the main cluster is superior to the masters of the extension cluster. The following are some of the
tasks performed by the master of the main cluster:
• Starting and stopping the Multicluster system
• Controlling and monitoring the masters of the extension cluster
• Communicating with the Multicluster Box
If the master of the main cluster stops operation, the entire Multicluster system shuts down. If a
generator is integrated in the stand-alone grid, it will take over the power supply to the loads in this
case.
Master
A configuration setting which assigns the leading role in a cluster to an off-grid inverter or backup
inverter. The master performs centralised control and monitoring tasks (e.g., frequency regulation,
battery management, generator control, and control of the Automatic Switch Box in the backup
system), which must be performed by just one device in a cluster. All other inverters in the cluster must
be configured to leave these tasks to the master, and to be controlled by the master (see Slave). The
master is also the device used to configure and operate the cluster, and record data centrally.
Multicluster Box
The Multicluster Box is the AC main distribution in the Multicluster system and a component of the
SMA Multicluster Technology. In a stand-alone grid the Multicluster Box connects the clusters with the
loads, the AC sources of the stand-alone grid, and the generator.
Multicluster system
A Multicluster system is made up of multiple clusters connected in parallel. The power of the
Multicluster system increases with the number of clusters. The clusters are connected in parallel via a
Multicluster Box. The size of the Multicluster Box is determined when the system is designed
depending on the power requirement.
