GE L90 Instruction Manual page 328

5.6 GROUPED ELEMENTS
SETTING
NEUTRAL DIR OC1
FUNCTION:
Disabled=0
Enabled=1
SETTING
AND
NEUTRAL DIR OC1 BLK:
Off=0
SETTING
NEUTRAL DIR OC1
SOURCE:
NEUTRAL DIR OC1 POL
VOLT:
NEUTRAL DIR OC1 OP
CURR:
}
Measured VX
Calculated V_0
Zero Seq Crt (I_0)
Ground Crt (IG)
SETTING
IG
NEUTRAL DIR OC1
POLARIZING:
5
Voltage OR
Current
Dual OR
NOTE:
1) CURRENT POLARIZING IS POSSIBLE ONLY IN RELAYS WITH
THE GROUND CURRENT INPUTS CONNECTED TO
AN ADEQUATE CURRENT POLARIZING SOURCE
2) GROUND CURRENT CAN NOT BE USED FOR POLARIZATION
AND OPERATION SIMULTANEOUSLY
3) POSITIVE SEQUENCE RESTRAINT IS NOT APPLIED WHEN
I _1 IS BELOW 0.8pu
5-182
SETTING
NEUTRAL DIR OC1 FWD
PICKUP:
NEUTRAL DIR OC1 OP
CURR:
NEUTRAL DIR OC1 POS-
SEQ RESTRAINT:
RUN
3( _0 - K _1 ) PICKUP
I I
OR
IG PICKUP
SETTINGS
AND
NEUTRAL DIR OC1 FWD
ECA:
NEUTRAL DIR OC1 FWD
LIMIT ANGLE:
NEUTRAL DIR OC1 REV
LIMIT ANGLE:
NEUTRAL DIR OC1
OFFSET:
RUN
FWD
}
-3V_0
REV
Voltage Polarization
0.05 pu
AND RUN
Current Polarization
SETTING
NEUTRAL DIR OC1 REV
PICKUP:
NEUTRAL DIR OC1 OP
CURR:
NEUTRAL DIR OC1 POS-
SEQ RESTRAINT:
RUN
3( _0 - K _1 ) PICKUP I I
OR
PICKUP
IG
Figure 5–90: NEUTRAL DIRECTIONAL OVERCURRENT LOGIC
L90 Line Current Differential System
AND
FWD
OR
AND
3I_0
REV
FWD
OR
REV
AND
5 SETTINGS
FLEXLOGIC OPERAND
AND NEUTRAL DIR OC1 FWD
1.25 cy
1.5 cy
FLEXLOGIC OPERAND
NEUTRAL DIR OC1 REV
827077AB.CDR
GE Multilin