Fronius Symo GEN24 10.0, Operating Instructions Manual, Page: 37 / 120

All-pin separation cabling variant, e.g. Germany,
France
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 limits spe-
cified by the country-specific standards.
- Establishing a proper ground connection for backup power mode to ensure the pro-
tection 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 nominal output of the inverter. Furthermore, the
performance of the connected battery must also be considered.
Transitioning
from feeding
energy into the
grid to backup
power mode 1. The public grid is monitored by the inverter's internal grid and system protection 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, K2, K4 and K5 drop out. This disconnects the backup power circuits
and the inverter from the rest of the home network and from the public grid, as the
main contacts of the contactors K1 and K2 open at all pins. The NC auxiliary con-
tacts of contactors K1 and K2 send feedback to the inverter that the contactors are
open (a condition for starting backup power mode).
4. The NC main contacts of contactors K4 and K5 are closed, establishing a connec-
tion 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 condition for starting backup power
mode).
5. The inverter activates relay K3, which interrupts the supply to contactors K1, K2, K4
and K5. This prevents unintentional activation of contactors K1, K2, 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 measure-
ments on the inverter terminals and the Smart Meter that the backup power mode
can be activated.
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.
37
EN