Breaker Failure Unit (50Bf); 50Bf Unit Setpoints - GE Multilin F650 Instruction Manual

5.5 CONTROL ELEMENTS
Note: The Switchgear element used in the Breaker Failure unit is the one configured in the Number of Switchgear
setpoint, inside Breaker setpoints at Setpoint > Protection Elements > Breaker > Breaker setpoints
The breaker failure unit is used to determine when a trip command sent to a breaker has not been executed within a
selectable delay. Most commonly it is a failure to open from the tripped breaker. In the event of a breaker failure, the 50BF
unit must issue a signal that will trip the rest of breakers connected at that time to the same busbar, and that can provide
fault current.
Comparing the current measured by the Relay with a setpoint level makes breaker failure detection. If after receiving a
breaker initiate signal, the current level were maintained over the setpoint level during a longer period than the set time, this
would indicate that the breaker that has received the opening command has not been able to open and clear the fault, and
the relay would issue the corresponding breaker failure signal.
F650 units incorporate 2 levels of current and time, together with a trip without current unit, and an internal arc detection
unit.
The breaker failure Initiate signal is configured at setpoint > Relay Configuration > Protection Elements. In the BRK
FAILURE INITIATE input, the user must select the desired signal for the breaker failure initiation.
The following table describes the breaker failure unit setpoints: Setpoint > Control Elements > Breaker Failure
Table 5–78: 50BF UNIT SETPOINTS
SETPOINT > CONTROL ELEMENTS > BREAKER FAILURE
SETPOINT DESCRIPTION
Function permission
Supervision (retrip) pickup level
5
Hiset pickup level
Lowset pickup level
Internal arc pickup level
Internal arc time delay
Retrip time delay
Hiset time delay
Lowset time delay
Second stage time delay
WITHOUT current unit time delay
Snapshot event generation
setpoints description for breaker failure unit:
Function permission (Function):
Supervision or retrip pickup level (Supervision Pickup):
Hiset pickup level (Hiset Pickup):
Lowset pickup level (Loset Pickup):
Internal arc pickup level (Internal Arc Pickup):
Internal arc time delay (Internal Arc Delay):
Supervision or Retrip time delay (Supervision Delay):
High-level time delay (Hiset Delay):
Low-level time delay (Lowset Delay):
2nd step time delay (2
No current unit time delay (No Current Delay):
5-94
NAME
Function
Supervision Pickup
Hiset Pickup
Lowset Pickup
Internal Arc Pickup
Internal Arc Delay
Supervision Delay
HiSet Delay
LowSet Delay
2nd Step Delay
No Current Delay
Snapshot Events
nd
Step Delay):
F650 Digital Bay Controller

5.5.6 BREAKER FAILURE UNIT (50BF)

DEFAULT VALUE STEP
DISABLED N/A
1.00 0.01 A
5.00 0.01 A
2.00 0.01 A
0.10 0.01 A
10.00 0.01 s
10.00 0.01 s
10.00 0.01 s
10.00 0.01 s
10.00 0.01 s
10.00 0.01 s
ENABLED N/A
This setpoint allows enabling and disabling the 50BF unit
Supervision level pickup current threshold
High-level pickup current threshold.
Low level pickup current threshold.
Internal arc unit pickup current threshold.
Time delay applied to the internal arc unit
Time delay applied to the supervision or retrip unit.
Time delay applied to the high level unit.
Time delay applied to the low level unit.
Time delay applied to the breaker failure second step.
Time delay applied to the trip without current unit.
5 SETPOINTS
RANGE
[DISABLED – ENABLED]
[0.05 : 160.00]
[0.05 : 160.00]
[0.05 : 160.00]
[0.05 : 160.00]
[0.00 : 900.00]
[0.00 : 900.00]
[0.00 : 900.00]
[0.00 : 900.00]
[0.00 : 900.00]
[0.00 : 900.00]
[DISABLED – ENABLED]
GE Multilin