4.211
Date Code 20170814
Instruction Manual
SEL-700G Relay
Protection and Logic Functions
Global Settings (SET G Command)
Breaker Failure
Setting
The SEL-700G provides flexible breaker failure logic for as many as two
breakers (see Figure 4.140). In the default breaker failure logic, the assertion
of the Relay Word bit TRIPm (m = X, Y) starts the associated BFD timer if the
sum of positive-sequence and negative-sequence currents is above 0.02 •
I
NOM
, where I
NOM
is nominal CT rating 1 or 5 A. If the current remains above
the threshold for the BFD delay setting, the Relay Word bit BFTm asserts. Use
BFTm to operate an output relay to trip appropriate backup breakers.
Changing the BFIm and/or 52ABF settings can modify the default breaker
failure logic (52ABF is a common setting that applies to both logic schemes).
➤
Set BFIX := R_TRIG TRIPX AND NOT IN102 if input
IN102
is
manual trip only and you do not want breaker failure initiation
when the tripping is caused by this input.
➤
Set 52ABF := Y if you want the breaker failure logic to detect a
failure of the breaker/contactor auxiliary contact to operate
during the trip operation, as defined by the BFIm setting.
Figure 4.140
Breaker Failure Logic
Table 4.66
Breaker Failure Setting
Setting Prompt
Setting Range
Setting Name :=
Factory Default
52A INTERLOCK
Y, N
52ABF := N
BRKRX FAIL DELAY
0.00–2.00 sec
BFDX := 0.50
BRKRX FAIL INIT
SEL
OGIC
BFIX := R_TRIG TRIPX
BRKRY FAIL DELAY
0.00–2.00 sec
BFDY := 0.50
BRKRY FAIL INIT
SEL
OGIC
BFIY := R_TRIG TRIPY
NOTE:
Breaker failure logic requires
that either X or Y-side CTs meter the
breaker currents. Do not use this
element if the appropriate current
inputs are not available in your
application. For example, Figure 2.17
connections do not provide breaker
currents to the relay.
(a) Breaker 52X Failure Logic
(b) Breaker 52Y Failure Logic
52ABF = Y
BFIY
Setting
52AY
0.02 • I
YNOM
| I1Y | + | I2Y |
BFDY
0
Relay
Word
Bit
BFTY
Relay
Word
Bit
BFIX
0.02 • I
YNOM
| I1Y | + | I2Y|
52ABF = Y
Setting
52AX
BFDX
0
Relay
Word
Bit
BFTX
Relay
Word
Bit
0.02 • I
XNOM
| I1X | + | I2X |
1
S1
2
NOTE: Switch S1 is set as follows:
Pos 1—If X_CUR_IN := TERM
Pos 2—If X_CUR_IN := NEUT
Summary of Contents for SEL-700G Series
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