5-94 F650 Digital Bay Controller GE Multilin
5.5 CONTROL ELEMENTS 5 SETPOINTS
5
5.5.6 BREAKER FAILURE UNIT (50BF)
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
setpoints description for breaker failure unit:
Function permission (Function): This setpoint allows enabling and disabling the 50BF unit
Supervision or retrip pickup level (Supervision Pickup): Supervision level pickup current threshold
Hiset pickup level (Hiset Pickup): High-level pickup current threshold.
Lowset pickup level (Loset Pickup): Low level pickup current threshold.
Internal arc pickup level (Internal Arc Pickup): Internal arc unit pickup current threshold.
Internal arc time delay (Internal Arc Delay): Time delay applied to the internal arc unit
Supervision or Retrip time delay (Supervision Delay): Time delay applied to the supervision or retrip unit.
High-level time delay (Hiset Delay): Time delay applied to the high level unit.
Low-level time delay (Lowset Delay): Time delay applied to the low level unit.
2nd step time delay (2
nd
Step Delay): Time delay applied to the breaker failure second step.
No current unit time delay (No Current Delay): Time delay applied to the trip without current unit.
SETPOINT > CONTROL ELEMENTS > BREAKER FAILURE
SETPOINT DESCRIPTION NAME DEFAULT VALUE STEP RANGE
Function permission Function DISABLED N/A [DISABLED – ENABLED]
Supervision (retrip) pickup level Supervision Pickup 1.00 0.01 A [0.05 : 160.00]
Hiset pickup level Hiset Pickup 5.00 0.01 A [0.05 : 160.00]
Lowset pickup level Lowset Pickup 2.00 0.01 A [0.05 : 160.00]
Internal arc pickup level Internal Arc Pickup 0.10 0.01 A [0.05 : 160.00]
Internal arc time delay Internal Arc Delay 10.00 0.01 s [0.00 : 900.00]
Retrip time delay Supervision Delay 10.00 0.01 s [0.00 : 900.00]
Hiset time delay HiSet Delay 10.00 0.01 s [0.00 : 900.00]
Lowset time delay LowSet Delay 10.00 0.01 s [0.00 : 900.00]
Second stage time delay 2nd Step Delay 10.00 0.01 s [0.00 : 900.00]
WITHOUT current unit time delay No Current Delay 10.00 0.01 s [0.00 : 900.00]
Snapshot event generation Snapshot Events ENABLED N/A [DISABLED – ENABLED]
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