GE T60, Instruction Manual

Page: 395 / 796

GE Multilin T60 Transformer Protection System 5-249
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.
5.6.10 BREAKER FAILURE (ANSI 50BF)
PATH: SETTINGS

GROUPED ELEMENTS

SETTING GROUP 1(6)

BREAKER FAILURE

BREAKER FAILURE 1(6)

BREAKER FAILURE 1

BF1 FUNCTION:
Disabled
Range: Disabled, Enabled
MESSAGE
BF1 MODE:
3-Pole
Range: 3-Pole, 1-Pole
MESSAGE
BF1 SOURCE:
SRC 1
Range: SRC 1, SRC 2, SRC 3, SRC 4, SRC 5, SRC 6
MESSAGE
BF1 USE AMP SUPV:
Yes
Range: Yes, No
MESSAGE
BF1 USE SEAL-IN:
Yes
Range: Yes, No
MESSAGE
BF1 3-POLE INITIATE:
Off
Range: FlexLogic operand
MESSAGE
BF1 BLOCK:
Off
Range: FlexLogic operand
MESSAGE
BF1 PH AMP SUPV
PICKUP: 1.050 pu
Range: 0.001 to 30.000 pu in steps of 0.001
MESSAGE
BF1 N AMP SUPV
PICKUP: 1.050 pu
Range: 0.001 to 30.000 pu in steps of 0.001
MESSAGE
BF1 USE TIMER 1:
Yes
Range: Yes, No
MESSAGE
BF1 TIMER 1 PICKUP
DELAY: 0.000 s
Range: 0.000 to 65.535 s in steps of 0.001
MESSAGE
BF1 USE TIMER 2:
Yes
Range: Yes, No
MESSAGE
BF1 TIMER 2 PICKUP
DELAY: 0.000 s
Range: 0.000 to 65.535 s in steps of 0.001