Generator And Grid - SMA Sunny Island 2012 Technical Description

SMA Solar Technology AG

13.3 Generator and Grid

In addition to the public grid, a generator can also be integrated into an island grid system as a
secondary protective measure. This is particularly useful in case of long-term grid failures, if after
some time the battery size no longer suffices either, to bridge the failure.
The standard solution in such cases is to use a transfer switch that can be purchased as a manual
or an automatic switch. By using such a switch, theAC2 connection, to which the public grid is
normally connected, switches to a connection with a diesel generator, as shown in the figure below:
To use such a switch, proceed with the installation as follows:
1. Connect the negative pole of the DigIn connection on the Sunny Island to the negative pole
of the BatVtgOut connection, also located on the Sunny Island.
2. Connect the positive pole of the DigIn connection to a NO connection of an auxiliary contact
of the transfer switch.
3. Connect the positive pole of the BatVtgOut connection to the second contact of the same
auxiliary contact on the transfer switch.
An auxiliary contact is used because the Sunny Island must "know" whether it is connected to the
public grid or whether it must manage a diesel generator.
To enable such operation, the "GenGrid" (GridBackup + Generator) selection is absolutely
imperative (see section 9.2 "Starting the Quick Configuration Guide (QCG)" (Page 76)).
Information
All the settings that you have performed for the generator and grid in the submenus also
apply to the "GridBackup + Generator" selection.
Technical Description
Connecting External Sources
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