SMA America, LLC
14 Connecting External Sources
Technical description
SI4548_6048-US-TB_en-13
131
14.2.5 Grid Reconnection
In stand-alone grid operation, the Sunny Island constantly checks whether the grid has been
reconnected (see above). The following conditions have to be fulfilled to guarantee that the
Sunny Island synchronizes with the transmission line and connects to the transmission line:
• The frequency of the utility grid must be between the values of the parameters
"232.05 GdFrqMin" and "232.06 GdFrqMax" for the time defined in the "232.07 GdVldTm"
parameter.
• The voltage of the utility grid has to be between the values of the parameters
"232.01 GdVtgMin" and "232.02 GdVtgMax" for the time defined in the "232.07 GdVldTm"
parameter.
14.2.6 Grid Operation
During grid operation, the utility grid and stand-alone grid are connected. The Sunny Island is
connected along with the stand-alone grid to the utility grid. In this case, the voltage and frequency
in both grids are identical.
In grid operation, the grid monitoring checks whether the permissible limits for voltage and frequency
(see Grid Reconnection) are exceeded, or grid failure, for taking over supply the stand-alone grid
system. For this, the utility grid is disconnected (grid replacement operation).
The battery is generally charged or its charge is maintained on the grid.
Charge Mode
Charge mode on the grid is indicated by energy flowing to the battery. The battery is charged until
the respective charge process (Boost, Full, Equalize) has been completed and the system changes to
float charge (Float) (see Section 13.4 "Charge Control", page 109).
Grid as generator: Charging the Sunny Island via the grid to avoid deep
discharge
Grid failures
All grid failures affect the stand-alone grid during grid operation.
Manual grid start deactivates settings for automatic grid start
Via the "560.01 GdManStr" parameter you can define whether the grid is to be connected or
not.
• "Stop": the utility grid will never be connected.
• "Start": the utility grid is always connected.
• "Auto": the utility grid connects automatically and protects the battery from deep discharge.
The following section describes how to perform the settings for an automatic grid start.
Summary of Contents for Sunny Island 4548-US
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