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

Load Current Circuit Breaker Failure Initiation: BFILC1
Circuit Breaker
Flashover Protection
Circuit Breaker
Failure Trip Logic
Unlatch Circuit Breaker Failure Trip Equation
Date Code 20151029
Program SEL control equation BFILC1 (load current breaker failure
OGIC
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 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.
The relay has dedicated circuit breaker failure trip logic (see Figure 3.170).
Set SEL control equation BFTR1 (breaker failure trip—BK1) to assert
OGIC
for circuit breaker failure trips from Relay Word bits FBF1, NBF1, LCBF1,
and FOBF1.
When this SEL control equation asserts, the relay sets Relay Word bit
OGIC
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.
Use SEL control equation BFULTR1 (breaker failure unlatch trip—BK1)
OGIC
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)
a
Setting Description
50FP1 Phase fault current pickup—BK1 (A)
BFPU1 Breaker failure time delay—BK1 (cycles)
SPBFPU1 Single-pole trip circuit breaker failure
time delay—BK1 (cycles)
RTPU1 Retrip time delay—BK1 (cycles)
RT3PPU1 Three-pole retrip time delay—BK1
(cycles)
BFI3P1 Three-pole breaker failure initiate—BK1
BFIA1 A-phase breaker failure initiate—BK1
BFIB1 B-phase breaker failure initiate—BK1
Protection Manual
Protection Functions
Circuit Breaker Failure Protection
Default
Range
(5 A)
0.50–50 6.000
0.000–6000 9.000
0.000–6000 6.000
0.000–6000 3.000
0.000–6000 3.000
SEL equation NA
OGIC
SEL equation NA
OGIC
SEL equation NA
OGIC
P.3.253
SEL-411L Relay