SMA
Solar Technology AG
Connecting External Sources
Technical Description
SI2012_2224-TEN082311
149
13.2.5 Grid Failure
A grid fault is characterized by the voltage or frequency being outside of the permissible limits (see
section 13.2.3 "Grid Reconnection" (Page 147)) 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 13.2.1 "Conditions" (Page 147)).
In case of a grid fault/failure, the public grid is disconnected and the inverter starts, if it is not already
running (silent mode).
13.2.6 Failures
Reverse Power
If the defined reverse power ("232.09 GdRvPwr" parameter) is exceeded for the time
"232.10 GdRvTm", the grid is disconnected. After reverse power, connection is blocked for at least
for the amount of time set at "232.07 GdVldTm".
Grid Failure
If a grid failure is detected (failure at the master phase), the grid is disconnected immediately.
Grid Phase Failure
The breakdown of a phase (e.g., blown fuse) at a slave device is treated as a phase breakdown.
The slave device then disconnects this phase. If the phase is detected as being available again, it is
reconnected.
The phase failure on the master device is treated as a grid failure (see above).
13.2.7 Limits and Power Adjustment
The Sunny Island burdens the generator at each phase with the current defined in the parameter
"233.03 GnCurNom". The power not directly used by the loads flows into the battery for charging.
At the same time, the limits for the AC charging current limit ("210.02 InvChrgCurMax" parameter)
on the Sunny Island and the DC charging current limit ("222.01 BatChrgCurMax" parameter) are
active. If the battery voltage reaches the charging voltage nominal value, it is also reduced (see
section 12.4 "Charge Control" (Page 122)).
If the current set using the "232.03 GdCurNom" parameter is not sufficient for powering the loads,
the battery provides support.
Information
If the Sunny Island is in silent mode when there is a public grid failure, there is a short
outage in the stand-alone grid (see chapter 12.4.5 "Silent Mode" (Page 127)).
