Permissive Echo Signaling - GE D60 Instruction Manual

SINGLE-POLE TRIPPING
Remote data
Bit pattern received
RX1 LOG1 RX2
0 0 1
0 0 0
1 1 0
0 1 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
1 1 0
0 1 0
0 0 1
0 0 0
0 0 0
0 0 0
1 1 0
0 1 0
0 0 1
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0

9.5.4 Permissive echo signaling

The "echo" feature can reduce the response time of an over-reaching scheme when a terminal is disconnected from the
line. In this condition, a zone 2 element at the terminal that remains in-service can detect a fault, but cannot trip, as a
permissive signal is not received from the remote terminal. This feature is provided in the permissive over-reaching transfer
trip and hybrid permissive over-reaching transfer trip schemes.
9.5.4.1 Permissive over-reaching transfer trip scheme
When used, this feature "echoes" a reliable received permissive signal back to the originating terminal when a line-end-
open condition is identified by the line pickup logic. The permissive echo is programmed as a one-shot logic. The echo is
sent only once and then the echo logic locks out for a settable period. The duration of the echo pulse does not depend on
the duration or shape of the received Rx signals but is settable.
The echo is sent back only if none of the overreaching protection elements operates.
9
9.5.4.2 Hybrid permissive over-reaching transfer trip permissive echo
When used, this feature "echoes" a reliable received permissive signal back to the originating terminal if the line-end-open
condition is recognized by the line pickup scheme and the fault is not identified as a reverse fault by the zone 4 or the
ground directional overcurrent function (if used). The permissive echo is programmed as a one-shot logic. The echo is sent
only once and then the echo logic locks out for a settable period. The duration of the echo pulse does not depend on the
duration or shape of the received Rx signal but is settable as
9-34
LOG2 RX3 LOG3 RX4
1 0 0 0
1 0 0 0
0 0 0 0
0 0 0 0
0 1 1 0
0 0 1 0
0 0 0 1
0 0 0 0
0 1 1 0
0 0 1 0
0 0 0 0
0 0 0 0
1 0 0 0
1 0 0 0
0 0 0 1
0 0 0 0
0 0 0 0
0 0 0 0
1 0 0 0
1 0 0 0
0 1 1 0
0 0 1 0
0 0 0 1
0 0 0 0
CHAPTER 9: THEORY OF OPERATION
Local data
Remote Local determination
determinatio of fault type
LOG4
n of fault
type
0 BG AG, AB, ABG, CA, CAG,
3P, unrecognized
0
0 AG BG
0
0 CG
0
1 MULTI-P
1
0 CG CG, BC, BCG, CA, CAG,
3P, unrecognized
0
0 AG CG
0
0 BG
0
1 MULTI-P
1
0 AG BC, BCG
0
0 BG CA, CAG
0
0 CG AB, ABG
0
1 MULTI-P 3P or unrecognized
1
.
ECHO DURATION
D60 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
Trip output
DCUB TRIP B
DCUB TRIP C
DCUB TRIP 3P