GE L90 Instruction Manual page 785

CHAPTER 10: THEORY OF OPERATION
The action output is generated per the following tables.
Table 10-17: Permissive scheme trip table for one-bit channels
Remote data
Bit pattern Remote
received determination of
fault type
RX1
1 Any
1 Any
1 Any
1 Any
Table 10-18: Blocking scheme trip table for one-bit channels
Remote data
Bit pattern Remote
received determination of
fault type
RX1
0 Any
0 Any
0 Any
0 Any
Table 10-19: Unblocking scheme trip table for one-bit channels
Remote data
Bit pattern received
RX1 LOG1
0 or 1 1
0 or 1 1
0 or 1 1
0 or 1 1
The scheme initiates a three-phase trip if the phase selector fails to recognize the fault type or after the
operand is asserted.
10.5.3.3 Two-bit channels
The TX1, TX2, RX1, and RX2 operands are used and fault data is coded per the following tables.
Table 10-20: Permissive scheme transmit codes for two-bit channels
Phase selector determination of
fault type
AG, BC, BCG
BG, CA, CAG
CG, AB, ABG, 3P, Unrecognized
L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
Local data
Local determination of fault type
AG Fault
BG Fault
CG Fault
AB, ABG, BC, BCG, CA, CAG, 3P,
Unrecognized
Local data
Local determination of fault type
AG Fault
BG Fault
CG Fault
AB, ABG, BC, BCG, CA, CAG, 3P,
Unrecognized
Local data
Remote Local determination of fault type
determination of
fault type
Any AG Fault
Any BG Fault
Any CG Fault
Any AB, ABG, BC, BCG, CA, CAG, 3P,
Unrecognized
Bit pattern transmitted
TX1 TX2
1 0
0 1
1 1
SINGLE-POLE TRIPPING
Trip output
Trip Phase A (A+N/G)
Trip Phase B (B+N/G)
Trip Phase C (C+N/G)
Trip Three Phases (per local selection,
unrecognized and 3P=A+B+C+N/G)
Trip output
Trip Phase A
Trip Phase B
Trip Phase C
Trip Three Phases
Trip output
DCUB Trip A
DCUB Trip B
DCUB Trip C
DCUB Trip 3P
AR FORCE 3P TRIP
10
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