The following points regarding cabling must be considered:
-
The main contacts of contactors K1 and K2 must be installed between the
Fronius Smart Meter and the residual-current circuit breaker of the inverter
and the residual-current circuit breaker of the backup power circuits.
-
The supply voltage for contactors K1 and K2 is provided by the public grid
and must be connected to phase 1 (L1) after the Fronius Smart Meter and
fused accordingly.
-
Actuation of contactors K1 and K2 is carried out by the external grid and sys-
tem protection unit.
-
The external grid and system protection unit must be installed after the
Fronius Smart Meter. Precise installation and wiring instructions for the ex-
ternal grid and system protection unit can be found in its separate Operating
Instructions.
-
The remote trip input of the external grid and system protection unit must
be set to NC according to the manufacturer's Operating Instructions.
-
To ensure residual-current circuit breakers function in backup power mode,
the connection between the neutral conductor and the ground conductor
must be established as close as possible to the inverter, but in any case be-
fore the first residual-current circuit breaker. An NC contact is used for this
purpose for the main contacts of contactors K4 and K5. This ensures that
the ground connection is established as soon as the public grid connection is
no longer available.
-
The supply voltage for contactors K1, K2, K4 and K5 is provided via phase 1
(L1) of the public grid and is switched via the external grid and system pro-
tection unit.
-
An NC contact for relay K3, which activates the remote input of the external
grid and system protection unit, interrupts the supply voltage to contactors
K1, K2, K4 and K5. This prevents the ground connection from being immedi-
ately disconnected again when power returns to the public grid and the
backup power network of the inverter from being switched to the public grid.
-
The NO contact of relay K3 gives additional feedback to the inverter on
whether the locking was successfully performed by relay K3.
-
Additional inverters or other AC sources can be installed in the backup
power circuit after the main contacts of K1 and K2. The sources are not syn-
chronised to the network of the inverter because this backup power network
has a frequency of 53 Hz.
Testing backup
power mode
Backup power mode should be tested once it has been installed and set up for
the first time. A battery state of charge of over 30% is recommended when in
test mode.
A description on how to run test mode can be found in the backup power check-
list (https://www.fronius.com/en/search-page, item number: 42,0426,0365).
87
EN
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