GE Grid Solutions F60, Instruction Manual

Page: 339 / 740

GE Multilin F60 Feeder Protection System 5-201
5 SETTINGS 5.6 GROUPED ELEMENTS
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.
5.6.8 NEGATIVE-SEQUENCE CURRENT
a) MAIN MENU
PATH: SETTINGS

GROUPED ELEMENTS

SETTING GROUP 1(6)

NEGATIVE SEQUENCE CURRENT
For additional information on the negative sequence time overcurrent curves, refer to the Inverse Time Overcurrent Curves
section earlier.

NEGATIVE SEQUENCE

CURRENT

NEG SEQ TOC1

See page 5–202.
MESSAGE

NEG SEQ TOC2

See page 5–202.
MESSAGE

NEG SEQ IOC1

See page 5–203.
MESSAGE

NEG SEQ IOC2

See page 5–203.
MESSAGE

NEG SEQ DIR OC1

See page 5–204.
MESSAGE

NEG SEQ DIR OC2

See page 5–204.