Test Example 2 - GE T35 UR Series Instruction Manual

9 COMMISSIONING
D/YG30° TRANSFORMER WITH PHASE A TO GROUND FAULT ON THE GROUNDED WYE.
Transformer: D/y30°, 20 MVA, 115/12.47 kv, CT1 (200:1), CT2 (1000:1)
I (f) = 0.577 pu 0°
A
A
I (f) = 0 pu
B
B
C
I (f) = 0.577 pu –180°
C
Figure 9–3: CURRENT DISTRIBUTION ON A D/YG30° TRANSFORMER WITH A LV-SIDE GROUND FAULT
TEST PHASE
W1 CURRENT
0.29 ∠0°
Balanced A
Condition
B
C 0.29 ∠–180°
Minimum A 0.137 ∠0°
Pickup
B
0.137 ∠–180°
C
0.108 ∠0°
Minimum A
Pickup
B
C 0.108 ∠–180°
Slope 1 A 0.4435 ∠0°
B
0.4435 ∠–180°
C
0.4425 ∠0°
Slope 1 A
B
C 0.4425 ∠–180°
1.2 ∠0°
Intermediate A
Slope 1 & 2
B
1.2 ∠–180°
C
Intermediate A 1.1 ∠0°
Slope 1 & 2
B
C 1.1 ∠–180°
0.4 ∠0°
Slope 2 A
B
0.4 ∠–180°
C
Slope 2 A 0.2 ∠0°
B
0.2 ∠–180°
C
GE Multilin
D/y30° Transformer
∠
∠
INJECTED CURRENT
W2 CURRENT
0.926 ∠–180°
0 ∠0° 0 ∠0°
0 ∠0°
0.521 ∠–180°
0 ∠0° 0 ∠0°
0 ∠0°
0.521 ∠–180°
0 ∠0° 0 ∠0°
0 ∠0°
1.6 ∠–180°
0 ∠0° 0 ∠0°
0 ∠0°
1.7 ∠–180°
0 ∠0° 0 ∠0°
0 ∠0°
5 ∠–180°
0 ∠0° 0 ∠0°
0 ∠0°
5 ∠–180°
0 ∠0° 0 ∠0°
0 ∠0°
15 ∠–180°
0 ∠0° 0 ∠0°
0 ∠0°
15 ∠–180°
0 ∠0° 0 ∠0°
0 ∠0°
T35 Transformer Protection System
9.2 DIFFERENTIAL CHARACTERISTIC TEST EXAMPLES
I (f) = 1 pu 0°
a
I (f) = 0
b
I (f) = 0
c
DISPLAYED CURRENT
DIFFERENTIAL RESTRAINT
0 ∠0° 0.5349 ∠–180°
0 ∠0° 0 ∠0°
0 ∠0° 0.5349 ∠0°
0.048 ∠0° 0.3 ∠–180°
0 ∠0° 0 ∠0°
0.048 ∠0° 0.3 ∠0°
0.102 ∠0° 0.3 ∠–180°
0 ∠0° 0 ∠0°
0.102 ∠0° 0.3 ∠0°
0.110 ∠0° 0.9026 ∠–180°
0 ∠0° 0 ∠0°
0 ∠0° 0 ∠0°
0.165 ∠0° 0.979 ∠–180°
0 ∠0° 0 ∠0°
0.165 ∠0° 0.979 ∠0°
0.675 ∠–180° 2.882 ∠–180°
0 ∠0° 0 ∠0°
0.675 ∠0° 2.882 ∠0°
0.860 ∠–180° 2.882 ∠–180°
0 ∠0° 0 ∠0°
0.860 ∠0° 2.882 ∠0°
7.915 ∠–180° 8.646 ∠–180°
0 ∠0° 0 ∠0°
7.915 ∠0° 8.646 ∠0°
7.918 ∠–180° 8.650 ∠–180°
0 ∠0° 0 ∠0°
7.916 ∠0° 8.650 ∠0°

9.2.3 TEST EXAMPLE 2

∠
A
Fault
B
C
828737A1.CDR
STATUS
Not Applicable
Block
I
= 0.048 < Min PKP
d
Operate
I
= 0.102 > Min PKP
d
Block
I I
/ = 11.9%
d r
Operate
I I
/ = 16.8%
d r
Block
I I
/ = 23.4%
d r
Operate
I I
/ = 29.8%
d r
Block
I I
/ = 91.5%
d r
Operate
I I
/ = 95.7%
d r
9
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