SMA MULTICLUSTER BOX 12 - Manual (Page 44)

13 Multicluster Technology Terms SMA Solar Technology AG
44 MC-BOX-12-3-20-BE-en-10 Operating Manual
13 Multicluster Technology Terms
Stand-alone grid
A stand-alone grid is a utility grid which is independent of the public energy supply. A stand-alone grid with Sunny Island
is designed as a single-phase or three-phase AC grid which integrates various kinds of power generators
(e.g., PV systems, small wind turbine systems and diesel generators).
Batteries for energy storage are also an integral part of stand-alone grids. The Sunny Island battery inverter forms a
stand-alone grid and maintains a stable energy supply by regulating all processes.
Cluster
A cluster is made up of three Sunny Island inverters and one battery. One Sunny Island inverter per line conductor, i.e.,
three Sunny Island inverters in total, are connected to form a three-phase stand-alone grid. Within the cluster,
one Sunny Island is the master, while the other two are slaves.
Multicluster system
A multicluster system is made up of several 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 as a function of the power requirement during system design.
Multicluster Box
The Multicluster Box is the main AC distribution board in the multicluster system and a component of the SMA multicluster
technology. The Multicluster Box connects the Sunny Island clusters with the loads and the power generators within a
stand-alone grid.
Master
The master is the control and communication center in a cluster. It carries out the following tasks:
• Switching slaves on and off
• Controlling and monitoring the slaves, e.g., regulating frequency and voltage
• Controlling battery charge and discharge
• Monitoring battery capacity and state of charge
• Storing cluster and battery data on SD memory card
• Requesting diesel generator
• Exchanging data with the masters of other clusters
• Updating both slaves after firmware updates
• Displaying system values and system states
• Central capture of user entries
Slave
A slave is a functional unit subordinated to the master. A slave receives its configuration settings, current firmware
updates, and start/stop commands from the master. It transmits its operating data to the master and executes commands
issued by the master.