GE G30 - Negative Sequence Current

5-182 G30 Generator Protection System GE Multilin
5.6 GROUPED ELEMENTS 5 SETTINGS
5
EXAMPLE 5: INTERNAL LOW-CURRENT, HIGH-LOAD SINGLE-LINE-TO-GROUND FAULT WITH NO FEED FROM
THE GROUND
Given the following inputs: IA = 1.10 pu ∠0°, IB = 1.0 pu ∠–120°, IC = 1.0 pu ∠120°, and IG = 0.0 pu ∠0°
The relay calculates the following values:
I_0 = 0.033 pu ∠0°, I_2 = 0.033 pu ∠0°, and I_1 = 1.033 pu ∠0°
Igd = abs(3 × 0.0333 + 0.0) = 0.10 pu, IR0 = abs(3 × 0.033 – (0.0)) = 0.10 pu, IR2 = 3 × 0.033 = 0.10 pu,
IR1 = 1.033 / 8 = 0.1292 pu, and Igr = 0.1292 pu
Despite very low fault current level the differential current is above 75% of the restraining current.
EXAMPLE 6: INTERNAL HIGH-CURRENT SINGLE-LINE-TO-GROUND FAULT WITH NO FEED FROM THE GROUND
Given the following inputs: IA = 10 pu ∠0°, IB = 0 pu, IC = 0 pu, and IG = 0 pu
The relay calculates the following values:
I_0 = 3.3 pu ∠0°, I_2 = 3.3 pu ∠0°, and I_1 = 3.3 pu ∠0°
Igd = abs(3 × 3.3 + 0.0) = 10 pu, IR0 = abs(3 × 3.3 – (0.0)) = 10 pu, IR2 = 3 × 3.3 = 10 pu, IR1 = 3 × (3.33–3.33) = 0
pu, and Igr = 10 pu
The differential current is 100% of the restraining current.
5.6.7 NEGATIVE SEQUENCE CURRENT
a) NEGATIVE SEQUENCE DIRECTIONAL OVERCURRENT (ANSI 67Q, IEC PDEF/PTOC)
PATH: SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1(6)  NEGATIVE SEQUENCE CURRENT  NEG SEQ DIR OC1(2)
 NEG SEQ DIR OC1

NEG SEQ DIR OC1
FUNCTION: Disabled
Range: Disabled, Enabled
MESSAGE
NEG SEQ DIR OC1
SOURCE: SRC 1
Range: SRC 1, SRC 2, SRC 3, SRC 4
MESSAGE
NEG SEQ DIR OC1
OFFSET: 0.00 Ω
Range: 0.00 to 250.00 ohms in steps of 0.01
MESSAGE
NEG SEQ DIR OC1
TYPE: Neg Sequence
Range: Neg Sequence, Zero Sequence
MESSAGE
NEG SEQ DIR OC1 POS-
SEQ RESTRAINT: 0.063
Range: 0.000 to 0.500 in steps of 0.001
MESSAGE
NEG SEQ DIR OC1 FWD
ECA: 75° Lag
Range: 0 to 90° Lag in steps of 1
MESSAGE
NEG SEQ DIR OC1 FWD
LIMIT ANGLE: 90°
Range: 40 to 90° in steps of 1
MESSAGE
NEG SEQ DIR OC1 FWD
PICKUP: 0.050 pu
Range: 0.015 to 30.000 pu in steps of 0.001
MESSAGE
NEG SEQ DIR OC1 REV
LIMIT ANGLE: 90°
Range: 40 to 90° in steps of 1
MESSAGE
NEG SEQ DIR OC1 REV
PICKUP: 0.050 pu
Range: 0.015 to 30.000 pu in steps of 0.001
MESSAGE
NEG SEQ DIR OC1 BLK:
Off
Range: FlexLogic operand
MESSAGE
NEG SEQ DIR OC1
TARGET: Self-reset
Range: Self-reset, Latched, Disabled