Fronius GEN24 Operating Instructions Manual page 25

Each time the inverter is restarted, the "Frequency Alternative Limit" does not
have to be set to "On" again, but the external signal to activate it must be sent
again. If it is not sent, the inner frequency limit value is used.
Parameter
"Frequency Alternative
Limits"
"Underfrequency f<"
"Underfrequency Time
f<"
"Overfrequency f>"
"Overfrequency Time
f>"
"Startup and Reconnection"
Before the inverter is allowed to connect, the connection conditions for voltage
and frequency must be fulfilled for a certain time.
A distinction is made between:
- "Startup": switching on the inverter during a normal startup process (e. g. at
sunrise) and
- "Reconnection": the reconnection of the inverter after a grid fault (see table
"Grid faults") (e. g. if a fault occurs in the AC grid during the day which
causes the inverter to disconnect).
Which limit values are used when checking the connection conditions depends
on whether a mains fault has occurred and which "Mode" is defined. The "Mode"
only influences the limit values and not the monitoring time. The monitoring time
is determined by the parameters described in "General" / "Startup and Recon-
nection". The monitoring time used depends on whether it is "Startup" or "Recon-
nection" and applies equally to frequency and voltage limits. After the grid mon-
itoring has expired, the previously mentioned "Interface Protection" values are
active. In backup power mode these "Startup and Reconnection" parameters are
not active.
Parameter
"Mode"
Description
Activate / deactivate alternative frequency limit val-
ues "On" / "Off"
Setting value of alternative underfrequency protec-
tion f< in [Hz]
Setting value of time for the alternative underfre-
quency protection f< in [s]
Setting value of alternative overfrequency protec-
tion f> in [Hz]
Setting value of time for the alternative overfre-
quency protection f> in [s]
Description
The following modes are available:
- "Startup Values are used for Startup / Recon-
nection Values are used for Reconnection": In
a normal startup process, the startup values
are used as connection conditions. When re-
connecting after a mains fault, the reconnec-
tion values are used as connection conditions.
- "Startup Values are used for Startup and Re-
connection": Regardless of the type of connec-
tion, the startup values are always used as con-
nection conditions.
- "Startup Values are used for Reconnection":
When reconnecting after a mains fault, the
startup values are used as reconnection condi-
tions. In a normal start-up procedure, the
"Frequency Inner Limits" f< and f>used as
connection conditions.
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