GE L60 Instruction Manual page 248

5.5 GROUPED ELEMENTS
d) NEUTRAL DIRECTIONAL OVERCURRENT (ANSI 67N)
PATH: SETTINGS GROUPED ELEMENTS
NEUTRAL
DIRECTIONAL OC1
5
There are two Neutral Directional Overcurrent protection elements available. The element provides both forward and
reverse fault direction indications the
put operand is asserted if the magnitude of the operating current is above a pickup level (overcurrent unit) and the fault
direction is seen as "forward or "reverse", respectively (directional unit).
The overcurrent unit responds to the magnitude of a fundamental frequency phasor of the either the neutral current calcu-
lated from the phase currents or the ground current. There are two separate pickup settings for the forward- and reverse-
looking functions, respectively. If set to use the calculated 3I_0, the element applies a "positive-sequence restraint" for bet-
ter performance: a small user-programmable portion of the positive–sequence current magnitude is subtracted from the
zero-sequence current magnitude when forming the operating quantity.
The positive-sequence restraint allows for more sensitive settings by counterbalancing spurious zero-sequence currents
resulting from:
• System unbalances under heavy load conditions.
5-146
SETTING GROUP 1(6)
NEUTRAL DIR OC1
FUNCTION: Disabled
NEUTRAL DIR OC1
MESSAGE
SOURCE: SRC 1
NEUTRAL DIR OC1
MESSAGE
POLARIZING: Voltage
NEUTRAL DIR OC1 POL
MESSAGE
VOLT: Calculated V0
NEUTRAL DIR OC1 OP
MESSAGE
CURR: Calculated 3I0
NEUTRAL DIR OC1 POS-
MESSAGE
SEQ RESTRAINT: 0.063
NEUTRAL DIR OC1
MESSAGE
OFFSET: 0.00 Ω
NEUTRAL DIR OC1 FWD
MESSAGE
ECA: 75° Lag
NEUTRAL DIR OC1 FWD
MESSAGE
LIMIT ANGLE: 90°
NEUTRAL DIR OC1 FWD
MESSAGE
PICKUP: 0.050 pu
NEUTRAL DIR OC1 REV
MESSAGE
LIMIT ANGLE: 90°
NEUTRAL DIR OC1 REV
MESSAGE
PICKUP: 0.050 pu
NEUTRAL DIR OC1 BLK:
MESSAGE
Off
NEUTRAL DIR OC1
MESSAGE
TARGET: Self-reset
NEUTRAL DIR OC1
MESSAGE
EVENTS: Disabled
NEUTRAL DIR OC1 FWD
×
I 3
=
op
L60 Line Phase Comparison Relay
NEUTRAL CURRENT
Range: Disabled, Enabled
Range: SRC 1, SRC 2, SRC 3, SRC 4
Range: Voltage, Current, Dual
Range: Calculated V0, Measured VX
Range: Calculated 3I0, Measured IG
Range: 0.000 to 0.500 in steps of 0.001
Range: 0.00 to 250.00
Range: –90 to 90° in steps of 1
Range: 40 to 90° in steps of 1
Range: 0.002 to 30.000 pu in steps of 0.001
Range: 40 to 90° in steps of 1
Range: 0.002 to 30.000 pu in steps of 0.001
Range: FlexLogic™ operand
Range: Self-reset, Latched, Disabled
Range: Disabled, Enabled
and
NEUTRAL DIR OC1 REV
( × )
I_0 K I_1
–
5 SETTINGS
NEUTRAL DIRECTIONAL OC1(2)
Ω
in steps of 0.01
operands, respectively. The out-
(EQ 5.19)
GE Multilin