ABB SACE Tmax XT2 User Manual

1SDH002031A1002 ECN000092998 Rev. B SACE Tmax XT2 – XT4 | 64
19 - ROCOF Protections
List
The ROCOF Protection package can be configured on all models as an additional software
package. It includes:
Name
Type of protection
Page
ROCOF
Frequency derivative
64
ROCOF
Protection
Function
ROCOF protection protects against rapid frequency variations: if the frequency varies faster than
the control variation f28 set in the Trip unit for a time greater than t28, the protection sends the
TRIP command.
Figure 23
The protection automatically cuts out if the maximum line-to-line voltage value is less than 30 V.
To verify and simulate the trip times based on all the parameters, see:
 Protection summary table with the operating characteristics (page 79)
 Chart with tripping curve (page 94)
Parameters
Parameter
Description
Default
Enable
Enables/disables protection and availability on menu of the
parameters
OFF
Trip Enable
Activates/deactivates the open command: if disabled, the alarm
and the lapsing of the protection time are managed only as
information
OFF
Threshold
f28
Defines the maximum permitted frequency fluctuation rate over the
time; if the limit is exceeded, protection is tripped.
The value is expressed as an absolute value (Hz/s) Fn), settable in
a range: 0.4 Hz/s .. 10 Hz/s with 0.2 Hz/s step
0.6 Hz/s
Trip
direction
Defines whether the protection monitors an increase (Up), a
decrease (Down) or both variations (Up or Down)
Up or
Down
Time t18
This is the trip time of the protection; the value is expressed in
seconds, which are settable in a range:
0.06 s .. 300 s, with 0.01 s step
3 s
Constraints, limitations, and additional functions
From the service connector (with Ekip Connect) or with system bus communication it is also
possible to access the block functions, see page70.

ABB SACE Tmax XT2 Specifications

General

Brand	ABB
Model	SACE Tmax XT2
Category	Circuit breakers
Language	English