GE D60 - Page 575

GE Multilin D60 Line Distance Protection System 8-25
8 THEORY OF OPERATION 8.5 SINGLE-POLE TRIPPING
8
If none of the fault types indicated above is determined, then three-phase fault conditions are checked to detect the pres-
ence of positive-sequence current and the absence of both zero-sequence and negative-sequence current. If these condi-
tions are met, then the
PHASE SELECT 3P FlexLogic operand is asserted; otherwise, the PHASE SELECT VOID operand is
asserted, indicating that the phase selector failed to identify the fault type.
Finally, the states of the following additional FlexLogic operands are determined.
The phase selector operands are reset ½ cycle after the
OPEN POLE OP FlexLogic operand is asserted or after delay
defined by the
PHASE SELECTOR RESET setting (in Trip Output element) once the disturbance detector (50DD) initially oper-
ated.
Figure 8–11: PHASE SELECTOR LOGIC
OPERAND DESCRIPTION
PHASE SELECT AG Asserted when a phase A to ground fault is detected.
PHASE SELECT BG Asserted when a phase B to ground fault is detected.
PHASE SELECT CG Asserted when a phase C to ground fault is detected.
PHASE SELECT AB Asserted when a phase A to B fault is detected.
PHASE SELECT BC Asserted when a phase B to C fault is detected.
PHASE SELECT CA Asserted when a phase C to A fault is detected.
PHASE SELECT ABG Asserted when a phase A to B to ground fault is detected.
PHASE SELECT BCG Asserted when a phase B to C to ground fault is detected.
PHASE SELECT CAG Asserted when a phase C to A to ground fault is detected.
OPERAND DESCRIPTION
PHASE SELECT SLG Asserted if any of PHASE SELECT AG, PHASE SELECT BG, or PHASE SELECT CG
operands is active.
PHASE SELECT MULTI-P Asserted if neither the PHASE SELECT SLG nor PHASE SELECT VOID operands are being
asserted.
837027A6.CDR
SRCn 50DD OP
OPEN POLE OP
SRCn VT FUSE FAIL OP
DISTANCE SOURCE:
AND
FLEXLOGIC OPERAND
FLEXLOGIC OPERAND
FLEXLOGIC OPERAND
SETTING
DELAY
SETTING
I_1
V_0
V_1
V_2
I_0
I_2
FLEXLOGIC OPERANDS
PHASE SELECT AG
RESET
START
PHASE SELECTOR
PHASE SELECT BG
PHASE SELECT CG
PHASE SELECT AB
PHASE SELECT BC
PHASE SELECT CA
PHASE SELECT ABG
PHASE SELECT BCG
PHASE SELECT CAG
PHASE SELECT 3P
PHASE SELECT SLG
PHASE SELECT MULTI-P
PHASE SELECT VOID
4 cycles
t
RST
0
0
DELAY
0
0.5 cycles
PHASE SELECTOR
RESET DELAY
From the Trip Output element