Sel 411L - Table 3.127 Circuit Breaker Failure Protection Logic Settings

P.3.253
Date Code 20151029 Protection Manual SEL-411L Relay
Protection Functions
Circuit Breaker Failure Protection
Load Current Circuit Breaker Failure Initiation: BFILC1
Program SELOGIC control equation BFILC1 (load current breaker failure
initiation) to initiate this scheme. For example, use the auxiliary contacts from
the circuit breaker to detect when the circuit breaker is open. Relay Word bit
LCBF1 asserts if Relay Word bit BFILC1 remains asserted for time LCPU1
and the relay detects load current.
Circuit Breaker
Flashover Protection
Circuit breaker failure protection during flashover conditions is independent
of the other circuit breaker protection functions. Use this protection either
alone or in addition to the other protection.
Use current flow to detect when an open circuit breaker pole flashes over. Set
BLKFOA1 to TPA or CLS1 to block flashover protection for six cycles if an
A-phase single-pole trip occurs, or when circuit breaker BK1 closes.
Figure 3.169 shows the flashover circuit breaker failure logic. Flashover timer
FOPU1 (flashover time delay—BK1) starts timing if the circuit breaker is
open and current exceeds setting 50FO1 (flashover current pickup—BK1).
The relay uses pole-open logic BnOPH to determine whether the circuit
breaker is open.
The output of the flashover protection is Relay Word bit FOBF1. Use this
output to activate an external alarm, retrip the circuit breaker, or energize a
lockout relay.
Circuit Breaker
Failure Trip Logic
The relay has dedicated circuit breaker failure trip logic (see Figure 3.170).
Set SEL
OGIC control equation BFTR1 (breaker failure trip—BK1) to assert
for circuit breaker failure trips from Relay Word bits FBF1, NBF1, LCBF1,
and FOBF1.
When this SEL
OGIC control equation asserts, the relay sets Relay Word bit
BFTRIP1 (breaker failure trip for circuit breaker BK1) to logical 1 until
BFTR1 deasserts, timer TDUR3D times out, and an unlatch or reset condition
is active.
Unlatch Circuit Breaker Failure Trip Equation
Use SELOGIC control equation BFULTR1 (breaker failure unlatch trip—BK1)
to define the conditions that unlatch the control outputs that assert during a
circuit breaker failure trip. BFULTR1 unlatches the circuit breaker trip
condition BFTRIP1.
Table 3.127 Circuit Breaker Failure Protection Logic Settings (Sheet 1 of 2)
Setting
a
Description Range
Default
(5 A)
50FP1 Phase fault current pickup—BK1 (A) 0.50–50 6.000
BFPU1 Breaker failure time delay—BK1 (cycles) 0.000–6000 9.000
SPBFPU1 Single-pole trip circuit breaker failure
time delay—BK1 (cycles)
0.000–6000 6.000
RTPU1 Retrip time delay—BK1 (cycles) 0.000–6000 3.000
RT3PPU1 Three-pole retrip time delay—BK1
(cycles)
0.000–6000 3.000
BFI3P1 Three-pole breaker failure initiate—BK1 SEL
OGIC equation NA
BFIA1 A-phase breaker failure initiate—BK1 SEL
OGIC equation NA
BFIB1 B-phase breaker failure initiate—BK1 SEL
OGIC equation NA