Negative Sequence Current - GE G30 Instruction Manual

CHAPTER 5: SETTINGS
Igd = abs(3 × 0.0333 + 0.05) = 0.15 pu, IR0 = abs(3 × 0.033 – (0.05)) = 0.05 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 100% of the restraining current.
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.

5.7.7 Negative sequence current

5.7.7.1 Menu
SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1(6)  NEGATIVE SEQUENCE CURRENT
 NEGATIVE SEQUENCE
 CURRENT
5.7.7.2 Negative sequence directional overcurrent (ANSI 67Q, IEC PDEF/PTOC)
SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1(6)  NEGATIVE SEQUENCE CURRENT  NEG SEQ DIR
OC1(2)
 NEG SEQ DIR OC1

G30 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL
 NEG SEQ DIR OC1


 NEG SEQ DIR OC2


NEG SEQ DIR OC1

FUNCTION: Disabled
NEG SEQ DIR OC1

SOURCE: SRC 1
NEG SEQ DIR OC1

OFFSET: 0.00 Ω
NEG SEQ DIR OC1

TYPE: Neg Sequence
NEG SEQ DIR OC1 POS-

SEQ RESTRAINT: 0.063
NEG SEQ DIR OC1 FWD

ECA: 75° Lag
NEG SEQ DIR OC1 FWD

LIMIT ANGLE: 90°
GROUPED ELEMENTS
See below
Range: Disabled, Enabled
Range: SRC 1, SRC 2, SRC 3, SRC 4
Range: 0.00 to 250.00 ohms in steps of 0.01
Range: Neg Sequence, Zero Sequence
Range: 0.000 to 0.500 in steps of 0.001
Range: 0 to 90° Lag in steps of 1
Range: 40 to 90° in steps of 1
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