CHAPTER 10: THEORY OF OPERATION
SINGLE-POLE TRIPPING
L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
10-43
10
The action output is generated per the following tables.
Table 10-17: Permissive scheme trip table for one-bit channels
Table 10-18: Blocking scheme trip table for one-bit channels
Table 10-19: Unblocking scheme trip table for one-bit channels
The scheme initiates a three-phase trip if the phase selector fails to recognize the fault type or after the
AR FORCE 3P TRIP
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
Remote data
Local data
Bit pattern
received
Remote
determination of
fault type
Local determination of fault type
Trip output
RX1
1
Any
AG Fault
Trip Phase A (A+N/G)
1
Any
BG Fault
Trip Phase B (B+N/G)
1
Any
CG Fault
Trip Phase C (C+N/G)
1
Any
AB, ABG, BC, BCG, CA, CAG, 3P,
Unrecognized
Trip Three Phases (per local selection,
unrecognized and 3P=A+B+C+N/G)
Remote data
Local data
Bit pattern
received
Remote
determination of
fault type
Local determination of fault type
Trip output
RX1
0
Any
AG Fault
Trip Phase A
0
Any
BG Fault
Trip Phase B
0
Any
CG Fault
Trip Phase C
0
Any
AB, ABG, BC, BCG, CA, CAG, 3P,
Unrecognized
Trip Three Phases
Remote data
Local data
Bit pattern received
Remote
determination of
fault type
Local determination of fault type
Trip output
RX1
LOG1
0 or 1
1
Any
AG Fault
DCUB Trip A
0 or 1
1
Any
BG Fault
DCUB Trip B
0 or 1
1
Any
CG Fault
DCUB Trip C
0 or 1
1
Any
AB, ABG, BC, BCG, CA, CAG, 3P,
Unrecognized
DCUB Trip 3P
Phase selector determination of
fault type
Bit pattern transmitted
TX1
TX2
AG, BC, BCG
1
0
BG, CA, CAG
0
1
CG, AB, ABG, 3P, Unrecognized
1
1