ABB RELION 620 Series Technical Manual page 536

Section 5
Protection-related functions
5.2
5.2.1
5.2.2
5.2.3
5.2.4
530
Circuit breaker failure protection 50BF
Identification
Function description
Circuit breaker failure protection
Function block
GUID-12D6BD6F-2B26-453D-B62F-FC134EC98931 V3 EN
Figure 252: Function block
Functionality
The breaker failure function 50BF is activated by trip commands from the protection
functions. The commands are either internal commands to the terminal or external
commands through binary inputs. The pickup command is always a default for three-
phase operation. 50BF includes a three-phase conditional or unconditional re-trip
function, and also a three-phase conditional back-up trip function.
50BF uses the same levels of current detection for both re-trip and back-up trip. The
operating values of the current measuring elements can be set within a predefined setting
range. The function has two independent timers for trip purposes: a re-trip timer for the
repeated tripping of its own breaker and a back-up timer for the trip logic operation for
upstream breakers. A minimum trip pulse length can be set independently for the trip
output.
The function contains a blocking functionality. It is possible to block the function outputs,
if desired.
Operation principle
The function can be enabled and disabled with the Operation setting. The corresponding
parameter values are "Enable" and "Disable".
IEC 61850 IEC 60617
identification identification
CCBRBRF 3I>/Io>BF
1MAC504801-IB E
ANSI/IEEE C37.2
device number
50BF
620 series ANSI
Technical Manual