Neutral Directional Overcurrent (Ansi 67N, Iec Pdef/Ptoc) - GE T60 Instruction Manual

5 SETTINGS
d) NEUTRAL DIRECTIONAL OVERCURRENT (ANSI 67N, IEC PDEF/PTOC)

PATH: SETTINGS GROUPED ELEMENTS
 NEUTRAL
 DIRECTIONAL OC1
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The neutral directional overcurrent element provides both forward and reverse fault direction indications the
and
OC1 FWD NEUTRAL DIR OC1 REV
ating 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 separate pickup settings for the forward-looking and
reverse-looking functions. If set to use the calculated 3I_0, the element applies a positive-sequence restraint for better per-
formance: 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.
GE Multilin
 
SETTING GROUP 1(6) NEUTRAL CURRENT
NEUTRAL DIR OC1
FUNCTION: Disabled
NEUTRAL DIR OC1
SOURCE: SRC 1
NEUTRAL DIR OC1
POLARIZING: Voltage
NEUTRAL DIR OC1 POL
VOLT: Calculated V0
NEUTRAL DIR OC1 OP
CURR: Calculated 3I0
NEUTRAL DIR OC1 POS-
SEQ RESTRAINT: 0.063
NEUTRAL DIR OC1
OFFSET: 0.00 
NEUTRAL DIR OC1 FWD
ECA: 75° Lag
NEUTRAL DIR OC1 FWD
LIMIT ANGLE: 90°
NEUTRAL DIR OC1 FWD
PICKUP: 0.050 pu
NEUTRAL DIR OC1 REV
LIMIT ANGLE: 90°
NEUTRAL DIR OC1 REV
PICKUP: 0.050 pu
NEUTRAL DIR OC1 BLK:
Off
NEUTRAL DIR OC1
TARGET: Self-reset
NEUTRAL DIR OC1
EVENTS: Disabled
operands, respectively. The output operand is asserted if the magnitude of the oper-
  
I 3 I_0 K I_1
= –
op
T60 Transformer Protection System
5.6 GROUPED ELEMENTS

NEUTRAL DIRECTIONAL OC1
Range: Disabled, Enabled
Range: SRC 1, SRC 2, SRC 3, SRC 4, SRC 5, SRC 6
Range: Voltage, Current, Dual, Dual-V, Dual-I
Range: Calculated V0, Aux. Voltage (VX)
Range: Calculated 3I0, Measured IG
Range: 0.000 to 0.500 in steps of 0.001

Range: 0.00 to 250.00 in steps of 0.01
Range: –90 to 90° in steps of 1
Range: 40 to 90° in steps of 1
Range: 0.006 to 30.000 pu in steps of 0.001
Range: 40 to 90° in steps of 1
Range: 0.006 to 30.000 pu in steps of 0.001
Range: FlexLogic operand
Range: Self-reset, Latched, Disabled
Range: Disabled, Enabled

5
NEUTRAL DIR
(EQ 5.38)
5-237