7-32
Inputs, Outputs, Timers, and Other Control Logic
Date Code 20011205
SEL-311B Instruction Manual
Timer pickup setting SV6PU provides retrip delay, if desired (can be set to zero). Timer dropout
setting SV6DO holds the retrip output (output contact OUT101) closed for extra time if needed
after the breaker failure initiate signal (IN101) goes away.
Timer pickup setting SV7PU provides breaker failure timing. Timer dropout setting SV7DO
holds the breaker failure trip output (output contact OUT102) closed for extra time if needed
after the breaker failure logic unlatches (fault detectors 50P1 and 50G1 dropout).
Note that Figure
7.25 suggests the option of having output contacts OUT103 and OUT104
operate as additional breaker failure trip outputs. This is done by making the following SEL
OGIC
control equation settings:
OUT103 = SV7T
(breaker failure trip)
OUT104 = SV7T
(breaker failure trip)
Additional Settings Example 2
The seal-in logic circuit in the dedicated breaker failure scheme in Figure
7.25 can be removed
by changing the SEL
OGIC
control equation setting SV7 to:
SV = IN101 * (50P1 + 50G1)
If the seal-in logic circuit is removed, optoisolated input IN101 (breaker failure initiate) has to be
continually asserted for a breaker failure time-out.
Timers Reset When Power Is Lost, Settings Are Changed, or Active Setting Group Is
Changed
If power is lost to the relay, settings are changed (for the active setting group), or the active
setting group is changed, the SEL
OGIC
control equation variables/timers are reset. Relay Word
bits SV
n
and SV
n
T (
n
= 1 through 16) are reset to logical 0 and corresponding timer settings
SV
n
PU and SV
n
DO load up again after power restoration, settings change, or active setting
group switch.
Preceding Figure
7.25 shows an effective seal-in logic circuit, created by use of Relay Word bit
SV7 (SEL
OGIC
control equation variable SV7) in SEL
OGIC
control equation SV7:
SV7 = (SV7 + IN101) * (50P1 + 50G1)
If power is lost to the relay, settings are changed (for the active setting group), or the active
setting group is changed, the seal-in logic circuit is “broken” by virtue of Relay Word bit SV7
being reset to logical 0 (assuming input IN101 is not asserted). Relay Word bit SV7T is also
reset to logical 0, and timer settings SV7PU and SV7DO load up again.
Summary of Contents for SEL-311B
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