Page 56 - MCCB-XT2-XT4

ABB | SACE Tmax XT

OF2 Protection Function
OF2 protection functions in the same way as OF protection: the protection sends a TRIP command if the
t grid frequency read by the unit exceeds threshold f18 for longer than t18.
f18 OF2 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).
t18
The protection excludes itself if the maximum value of the line-to-line voltage is less than 30 V.
f 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 76)
• the graph with trip curve (page 88)
Parameters

Parameter Description Default
Activates/deactivates the protection and its availability in the
Enable OFF
parameters menu
Activates/deactivates transmission of the open command: if
Trip Enable disabled, the alarm and exceedance of protection time are only OFF
managed as information
Establishes the value that activates the protection.
The value is given as both absolute value (Hertz) and relative
Threshold f18 1,1 Fn
value (Fn) and can be set within the range: 1 Fn to 1.1 Fn in 0.001
Fn steps
This is the trip time of the protection; the value is given in
Time t18 seconds and can be set within a range: 0.06 s to 300 s, in 0.01 s 3 s
steps

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 70).

54 | © 2022 ABB | 1SDH002031A1002 - ECN000212994 Protections | 5 - Frequency protections