Automatic switch to backup power all-pin separa-
tion, e.g. Germany, France, Spain
Functions
-
Measuring and transferring the required parameters for energy management
and Solar.web by the Fronius Smart Meter.
-
Disconnecting from the public grid to enable operation in backup power
mode if the grid parameters are outside the country-specific standards.
-
Reconnecting to the public grid when the grid parameters are within the lim-
its specified by the country-specific standards.
-
Establishing a proper ground connection for backup power mode to ensure
the protection devices function correctly.
-
Option of having a separate backup power circuit or several backup power
circuits that are supplied even during failure of the public grid. The total load
of the backup power circuits must not exceed the rated power of the invert-
er. Furthermore, the performance of the connected battery must also be
considered.
Transitioning
from feeding en-
ergy into the grid
to backup power
mode
1.
The public grid is monitored by the inverter's internal grid and system pro-
tection unit and by the Fronius Smart Meter connected to it.
2.
Failure of the public grid.
3.
The inverter carries out the necessary measures according to the country
standard and then switches off.
Contactors K1, K4 and K5 drop out. This disconnects the emergency power
circuits and the inverter from the rest of the home network and from the
public grid, as the main contacts of contactor K1 open (all-pin). The NC auxil-
iary contacts of contactor K1 send feedback to the inverter that the contact-
or is open (a condition for starting backup power mode).
4.
The NC main contacts of contactors K4 and K5 are closed, establishing a
connection between the neutral conductor and the ground conductor. The
two other NC main contacts of contactors K4 and K5 give feedback to the
inverter that the ground connection has been established correctly (a condi-
tion for starting backup power mode).
5.
The inverter activates relay K3, which interrupts the supply to contactors K1,
K4 and K5. This prevents unintentional activation of contactors K1, K4 and
K5 and thus a grid connection when voltage is restored in the grid.
6.
The NO contact of relay K3 gives additional feedback to the inverter on
whether the locking was successfully performed by relay K3.
7.
The inverter decides based on the contactors' feedback as well as the meas-
urements on the inverter terminals and the Smart Meter that backup power
mode can be started.
8.
After all the required activation tests have been carried out, the inverter
starts backup power mode.
9.
All loads in the backup power circuits are supplied with power. The remaining
loads are not supplied with power and are safely isolated.
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