5 SETTINGS
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.
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PATH: SETTINGS
GROUPED ELEMENTS
NEGATIVE SEQUENCE
CURRENT
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
For additional information on the negative sequence time overcurrent curves, refer to the Inverse Time Overcurrent Curves
section earlier.
GE Multilin
SETTING GROUP 1(6)
NEGATIVE SEQUENCE CURRENT
NEG SEQ TOC1
NEG SEQ TOC2
NEG SEQ IOC1
NEG SEQ IOC2
NEG SEQ DIR OC1
NEG SEQ DIR OC2
F60 Feeder Protection System
5.6 GROUPED ELEMENTS
5.6.8 NEGATIVE-SEQUENCE CURRENT
See page 5–202.
See page 5–202.
See page 5–203.
See page 5–203.
See page 5–204.
See page 5–204.
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