ABB | SACE Tmax XT
62 | © 2020 ABB | 1SDH001821A1002 - ECN000135670
Protections | 10 - Frequency protections
OF2 Protection
f18
t
t18
f
OF2
Function
OF2 protection functions in the same way as OF protection: the protection sends a TRIP command if the grid
frequency read by the unit exceeds threshold f18 for longer than t18.
It is independent of OF protection, thus thresholds and functions of the two protections can be programmed
so as to take advantage of different plant solutions (example: signaling with OF and open command with OF2
or vice versa, or both for signaling or tripping).
The protection excludes itself if the maximum value of the line-to-line voltage is less than 30 V.
To check and simulate the trip times in relation to all the parameters, please consult:
• summary table of the protections with the operating characteristics (page 88)
• the graph with trip curve (page 102)
Parameters
Parameter
Description
Default
Enable
Activates/deactivates the protection and its availability in the
parameters menu
OFF
Trip Enable
Activates/deactivates transmission of the open command: if disabled,
the alarm and exceedance of protection time are only managed as
information
OFF
Threshold f18
Establishes the value that activates the protection.
The value is given as both absolute value (Hertz) and relative value (Fn)
and can be set within the range: 1 Fn to 1.1 Fn in 0.001 Fn steps
1,1 Fn
Time t18
This is the trip time of the protection; the value is given in seconds and
can be set within a range: 0.06 s to 300 s, in 0.01 s steps
3 s
Limitations and additional functions
The block functions can also be accessed by means of the service connector (via Ekip Connect) or by
connection to the system bus (page 78).
