GE 889 - Page 344

4–214 889 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL
PROTECTION CHAPTER 4: SETPOINTS
Figure 4-78: Negative Sequence Directional Overcurrent Protection logic diagram
AND
AND
AND
AND
NOTE: V_2 is negative-sequence voltage I_2 is negative-sequence current
AND
SETTING
Off = 0
Block
SETTINGS Forward Pickup Positive-Sequence Restraint
TIMER
1.25 cycles
1.5 cycles
FLEXLOGIC OPERAND
NegSeq DirOC FWD
SETTING
Disabled = 0
Enabled = 1
Function ACTUAL VALUES V_2 I_2
RUN
( |I_2| – × |I_1| ) PickupK ≥
Voltage Polarization
SETTINGS Forward ECA
RUN Forward Limit Angle Reverse Limit Angle
Forward
Reverse
SETTINGS Reverse Pickup RUN
( |I_2| – × |I_1| ) PickupK ≥
Pos Seq Restraint
FLEXLOGIC OPERAND
NegSeq DirOC REV
892725A1.cdr
TO NEG SEQ TOC AND IOC ELEMENTS
TO NEG SEQ TOC AND IOC ELEMENTS