Characteristic
Value
±1.5 % of the set value or ±0.002 × I
n
Ratio I2f/I1f measurement:
±5.0 % of the set value
Reset time
+35 ms / -0 ms
Reset ratio
Typically 0.96
Operate time accuracy
+35 ms / -0 ms
5.2
Circuit breaker failure protection CCBRBRF (ANSI
50BF)
5.2.1
Identification
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Circuit breaker failure protection
CCBRBRF
3I>/Io>BF
50BF
5.2.2
Function block
Figure 659: Function block
5.2.3
Functionality
The circuit breaker failure protection function CCBRBRF 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
start command is always a default for three-phase operation. CCBRBRF includes
a three-phase conditional or unconditional retrip function, and also a three-phase
conditional back-up trip function.
CCBRBRF uses the same levels of current detection for both retrip 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 retrip 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.
Protection related functions
1MRS759142 F
1162
REX640
Technical Manual