Page 3–6
UPLC™ Application Manual
SCHEME FOR EXTERNAL AND INTERNAL FAULTS
SCHEME FOR EXTERNAL AND INTERNAL FAULTS
Internal (FI) P1 operates.
f1 channel to unblock.
Loss of block and/ or receipt
of unblock (f2) operates RR
or inputs AND.
Trip.
P2 operates.
f2 channel shifts to unblock.
Loss of block and/or receipt
of unblock (f1) operates RR
or inputs AND.
Trip.
Type of Fault
Events at Station G
Events at Station H
Table 3–1. Operation of the Directional Comparison Unblocking Scheme.
External (FE) P1 operates.
f1 channel shifts to unblock.
f2 channel continues to
block.
No trip.
P2 does not see fault.
Loss of block and/or receipt
of unblock (f1) operates RR
or inputs AND.
No trip.
Table 3–2. Operation of the Underreaching Transfer Trip Scheme.
Type of Fault
Events at Station G
Events at Station H
External (FE) P1 does not operate.
No channel signal sent to H.
No trip.
P2 does not operate.
No channel signal sent to G.
No trip.
Internal (FI)
(Fault near station H)
P1 does not operate.
No channel signal sent to H.
†(FD
1 operates).
Transfer-trip (f2) from sta-
tion H operates RR or
inputs to AND (or OR if non-
permissive).
Trip.
P2 operates and trips direct-
ly.
Transfer-trip signal keyed to
station G.
†(FD
2 operates).
Trip.
† Omitted in non-permissive systems.
Summary of Contents for UPLC CU44-VER04
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