GE L90

CHAPTER 10: THEORY OF OPERATION SINGLE-POLE TRIPPING
L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL 10-45
10
Table 10-25: Unblocking scheme trip table for two-bit channels
10.5.3.4 Four-bit channels
The TX1, TX2, TX3, TX4, RX1, RX2, RX3, and RX4 operands are used.
0 0 CG, AB, ABG, 3P, Unrecognized AB, ABG, 3P, Unrecognized DIR BLOCK TRIP 3P
0 1 AG, BC, BCG BC, BCG Unrecognized
1 0 BG, CA, CAG CA, CAG Unrecognized
Remote data Local data
Bit pattern received Remote determination
of fault type
Local determination of
fault type
Trip output
RX1 LOG1 RX2 LOG2
1 1 0 0 AG, BC, BCG AG, AB, ABG CA, CAG, 3P DCUB TRIP A
010 0
0 0 1 1 BG, CA, CAG AG
000 1
1 1 1 1 CG, AB, ABG, 3P,
unrecognized
AG
011 1
110 1
010 1
0 0 1 1 BG, CA, CAG BG, AB, ABG BC, BCG, 3P DCUB TRIP B
000 1
1 1 1 1 CG, AB, ABG, 3P,
unrecognized
BG
011 1
110 1
010 1
1 1 0 0 AG, BC, BCG BG
010 0
1 1 0 0 AG, BC, BCG CG DCUB TRIP C
010 0
0 0 1 1 BG, CA, CAG CG
000 1
1 1 1 1 CG, AB, ABG, 3P,
unrecognized
CG, BC, BCG, CA, CAG
011 1
110 1
010 1
1 1 0 0 AG, BC, BCG BC, BCG, unrecognized DCUB TRIP 3P
010 0
0 0 1 1 BG, CA, CAG CA, CAG, unrecognized
000 1
1 1 1 1 CG, AB, ABG, 3P,
unrecognized
AB, ABG, 3P, unrecognized
011 1
110 1
010 1
Remote data Local data
Bit pattern received Remote determination of fault
type
Local determination of fault
type
Trip output
RX1 RX2