SMA Sunny Island 5048 - Grid Failure; Limits and Power Adjustment

Connecting External Sources SMA Technologie AG
Page 112 SI5048-11:EE4206 Technical Description
AC feed-in generators on the stand-alone grid side (Sunny Boys) can feed their energy
into the grid through the internal transfer relay of the Sunny Island 5048, for limitations,
see section 14.2.7 "Limits and Power Adjustment" (Page 112).
14.2.6 Grid Failure
A grid fault is characterized by the voltage or frequency being outside of the
permissible limits (see section 14.2.4 "Grid Reconnection" (Page 111)) or the main
power grid being disconnected. In this case, the time limits are relevant: Smaller
deviations are permitted for longer than large deviations (see section 14.2.1
"Conditions" (Page 110)).
In case of a grid fault/failure, the main power grid is disconnected and the inverter
starts, if it is not already running (silent mode).
14.2.7 Limits and Power Adjustment
The Sunny Island 5048 charges the generator during each phase using the current
specified in the "#242.03 GnCurNom" parameter. The power that is not directly used
by the loads flows into the battery for charging. The limits for the AC charging current
limit ("#210.02 InvChrgCurMax" parameter) on the Sunny Island 5048 and the DC
charging current limit ("#222.01 BatChrgCurMax" parameter) are active at the same
time. If the battery voltage reaches the charging voltage nominal value, it is also
reduced (see section 13.4 "Charge Control" (Page 88)).
If the current set using the "#250.03 GnCurNom" parameter is not sufficient for
powering the loads, the battery provides support.
The "#230.03 RtCurCps" parameter determines the partitioning of the reactive power
between the Sunny Island 5048 and generator or grid. In the external setting (default),
an attempt is made to provide the full reactive power through the Sunny Island 5048.
In the internal setting, an attempt is made to keep the full reactive power away from the
Sunny Island 5048. The shared setting divides the reactive power between the Sunny
Island 5048 and the generator or grid.
The feedback into the grid must be set to GridFeed using the "#250.08 GdMod"
parameter. However, the reverse power is not monitored.
In order to allow electricity to be fed from the battery into the grid, the battery
voltage in a charged battery (on the grid) must be increased by external DC
chargers above the nominal charging voltage.
A grid failure occurring while the Sunny Island 5048 is in silent mode can cause
a temporary grid failure in the stand-alone grid.