SUNNY ISLAND 5048 - Technical Description - Wind & Sun Ltd.

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14.2.4 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 supply grid and connects to the supply grid:
• The frequency of the power distribution grid has to be between the values of the
"232.05 GdFrqMin" and "232.06 GdFrqMax" parameter for the time defined in the
"232.07 GdVldTm" parameter.
• The voltage of the power distribution grid has to be between the values of the
"232.01 GdVtgMin" and 5V below the "232.02 GdVtgMax" parameter for the time defined
in the "232.07 GdVldTm" parameter.
14.2.5 Grid Operation
During grid operation, the power distribution grid and stand-alone grid are connected.
The Sunny Island is connected along with the stand-alone grid system to the power distribution 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 maintained or whether the grid fails to assume powering the stand-alone
grid system. For this, the power distribution 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 99)).
Silent Mode
Grid failures
All grid failures affect the stand-alone grid during grid operation.
In order to save energy, the silent mode can be activated using the "224.01 SilentEna" parameter set
to "enable" (default: disable). In this case, the Sunny Island is set to standby mode if the charge has
been completed and the battery has been in float charge for some time (see section 13.4.5 ”Silent
Mode” (page 103)).
The silent mode is exited regularly to recharge the battery.
In a single-phase parallel system, the grid failure is not detected on the individual Sunny Island. This
reaction occurs if the Sunny Island is individually fuse-protected on the grid side and the individual
fuses are separately tripped.
124 SI5048-TB-TEN110340 Technical Description