Rocof Protections - ABB SACE Emax 2 Series Operating Instructions Manual

7 - ROCOF protections

ROCOF Protection
t
f28
t28
81 | © 2023 ABB | 1SDH001330R1002 - ECN000297030
The ROCOF Protection package is available by default for Ekip G Hi-Touch and configurable in the
remaining models as additional SW package
The protection is described below:
Function
ROCOF protection protects against rapid frequency variations: the protection sends a TRIP command if
the frequency changes faster than control variation f28 set in the unit for longer than t28.
ROCOF
f(Hz)
Hz/s
f
mis
Figure 26
example with positive linear variation of the higher frequency of the set f28 value; the protection
(1)
also manages negative variations
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 96)
• the graph with trip curve (page 112)
Parameters
Parameter Description
Activates/deactivates the protection and its availability in the
Enable
parameters menu
Activates/deactivates transmission of the open command: if disabled,
Trip Enable the alarm and exceedance of protection time are only managed as
information
establishes the maximum admissible frequency variation rate over
Threshold time; the protection trips if this rate is exceeded.
f28 The value is given as absolute value (Hz/s) Fn) and can be set within
the range: 0.4 Hz/s to 10 Hz/s in 0.2 Hz/s steps
Trip
Establishes whether the protection monitors an increase (Up), a
decrease (Down) or both variations (Up and Down)
Direction
This is the trip time of the protection; the value is given in seconds
Time f28
and can be set within a range: 0.06 s to 300 s, in 0.01 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 86).
Frequency variation
after failure
Frequency fluctuation
(after a failure)
ABB | SACE Emax 2
(1)
f
28
t t
28 (s)
Default
OFF
OFF
0,6 Hz/s
Up or Down
0,5 s
Ekip Touch - Protections
7 - ROCOF protections