GE L90, Инструкция по эксплуатации

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CHAPTER 10: THEORY OF OPERATION SINGLE-POLE TRIPPING
L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL 10-41
10
If none of the fault types outlined in the table is determined, then three-phase fault conditions are checked to detect the
presence of positive-sequence current and the absence of both zero-sequence and negative-sequence current. If these
conditions 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.
Table 10-13: FlexLogic operands asserted
The phase selector operands are reset a half cycle after the
OPEN POLE OP
FlexLogic operand is asserted or after delay
defined by the
PHASE SELECTOR RESET
setting (in the Trip Output element) once the disturbance detector (50DD) initially
operated.
Figure 10-16: Phase selector logic
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
Operand Description