7-40
Inputs, Outputs, Timers, and Other Control Logic
Date Code 20010625
SEL-311L Instruction Manual
This puts the high-speed tripping contacts only under control of the backup protection, so
SEL
OGIC
control equations can qualify line current differential tipping decisions. Include Relay
Word bit TRIP87 in the TR SEL
OGIC
control equation. Include Relay Word bit TRIP in the
SEL
OGIC
control equations for trip contacts OUT201 and OUT202. Qualify 87L tripping with
the recloser shot counter, so instantaneous tripping is available during recloser shot 0, and
delayed tripping is available for other recloser shots. Create the delayed 87L protection for use
with later shots using a SEL
OGIC
Timer/Variable.
OUT201 = TRIP
OUT202 = TRIP
TR = TRIP87 * SH0 + SV1T + T51PT + T51QT + T50PT + T50QT . . .
SV1 = TRIP87
Delay SV1T assertion for the maximum expected clearing time for a fault downstream of the
tapped load fuse, e.g.,
SV1PU = 60
SV1DP = 0
Finally, torque control the tapped-load coordination elements to operate only for internal faults.
T51PTC = 87LA + 87LB + 87LC
T51QTC = 87L2
T50PTC = 87LA + 87LB + 87LC
T50QTC = 87L2
Connect contact OUT201 and OUT202 directly to the circuit breaker trip coils as shown in
Figure 7.28. Optionally include contacts OUT101 and OUT102 as shown in Figure 7.29 and set
OUT101 = TRIP
OUT102 = TRIP
See
Settings Example: 230 kV Transmission Line With Tapped Load
in
Section 9: Setting the
Relay
for more information regarding coordination with tapped loads.
Summary of Contents for SEL-311L
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