Questions Regarding Multicluster Systems - SMA SUNNY ISLAND 4.4M Operating Manual

SMA Solar Technology AG
• Select Generator > Generator and set the parameter Frequency monit. generator lower minimum
threshold to the minimum frequency of the generator voltage.
It may be that the permissible time for reverse power was exceeded (see Generator > Generator > Power
monitoring > Volt. monit. gener. max. reverse power trip. time).
• Check whether the warning Reverse power prot. (generator) has been entered in the menu Events.
• Select Generator > Generator > Operation and set the parameter Acknowledge generator errors to
Execute. This acknowledges the generator error.
The Sunny Island does not reconnect to the generator after disconnection from the generator due
to non-compliance with the thresholds for voltage and frequency – why?
The Sunny Island is switched with a hysteresis, i.e., the thresholds for connection do not correspond to the thresholds
for disconnection.
• To unload the generator, disconnect unnecessary loads.
• Wait until the voltage and frequency have reached the nominal values.

15.4.4 Questions Regarding Multicluster Systems

Extension clusters remain in standby mode even though the main cluster is in inverter mode?
The data cable between the masters of the individual clusters might not be connected. The master of the main cluster
cannot forward the "Start" command to the masters of the extension clusters.
Why is the multicluster system not supplying full power?
An extension cluster or individual Sunny Island inverters of an extension cluster might have failed.
Why are high levels of energy being transferred between the clusters in the multicluster system?
The state of charge of the batteries might differ temporarily. The off-grid system equalizes different states of charge
automatically.
The nominal frequencies and nominal voltages may be defined differently.
• Select Device > Inverter and set the parameters Inverter nominal voltage and Inverter nominal frequency
to the same value for all masters.
The battery capacities might differ significantly.
• Distribute the battery capacities to the clusters as evenly as possible.
Individual battery cells of a battery might have failed.
• Disconnect defective battery cells and set the new rated voltage and capacity (see Section 14.9 "Replacing the
Battery", page 140).
Operating Manual
15 Troubleshooting
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