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8-12
T35 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
DIFFERENTIAL CHARACTERISTIC TEST EXAMPLES
CHAPTER 8: COMMISSIONING
8
Figure 8-5: Current distribution of D/D transformer with an a to b fault on the LV side
Test
Phase
Injected current
Displayed current
Status
W1 current
W2 current
Differential
Restraint
Balanced
Condition
A
0
∠
0°
0
∠
0°
0
∠
0°
0
∠
0°
Not Applicable
B
0.435
∠
–90°
0.8
∠
–270°
0
∠
0°
0.8
∠
–270°
C
0.435
∠
–270°
0.8
∠
–90°
0
∠
0°
0.8
∠
–90°
Min Pickup
A
0
∠
0°
0
∠
0°
0
∠
0°
0
∠
0°
Block
I
d
= 0.065 < Min PKP
B
0.09
∠
–90°
0.23
∠
–270°
0.065
∠
0°
0.230
∠
–270°
C
0.09
∠
–270°
0.23
∠
–90°
0.065
∠
0°
0.230
∠
–90°
Min Pickup
A
0
∠
0°
0
∠
0°
0
∠
0°
0
∠
0°
Operate
I
d
= 0.101 > Min PKP
B
0.21
∠
–90°
0.486
∠
–270°
0.102
∠
0°
0.486
∠
–270°
C
0.21
∠
–270°
0.486
∠
–90°
0.101
∠
0°
0.486
∠
–90°
Slope 1
A
0
∠
0°
0
∠
0°
0
∠
0°
0
∠
0°
Block
I
d
/
I
r
= 14% < 15%
B
0.651
∠
–90°
1.39
∠
–270°
0.195
∠
0°
1.39
∠
–270°
C
0.651
∠
–270°
1.39
∠
–90°
0.195
∠
0°
1.39
∠
–90°
Slope 1
A
0
∠
0°
0
∠
0°
0
∠
0°
0
∠
0°
Operate
I
d
/
I
r
= 16.8% > 15%
B
0.63
∠
–90°
1.39
∠
–270°
0.233
∠
0°
1.39
∠
–270°
C
0.63
∠
–270°
1.39
∠
–90°
0.233
∠
0°
1.39
∠
–90°
Intermediate
Slope 1 & 2
A
0
∠
0°
0
∠
0°
0
∠
0°
0
∠
0°
Block
I
d
/
I
r
= 52.6%
< 60%
computed
B
1.2
∠
–90°
4.63
∠
–270°
2.44
∠
–270°
4.63
∠
–270°
C
1.2
∠
–270°
4.63
∠
–90°
2.44
∠
–90°
4.63
∠
–90°
Intermediate
Slope 1 & 2
A
0
∠
0°
0
∠
0°
0
∠
0°
0
∠
0°
Operate
I
d
/
I
r
= 68.8%
> 60%
computed
B
0.8
∠
–90°
4.63
∠
–270°
3.18
∠
–270°
4.63
∠
–270°
C
0.8
∠
–270°
4.63
∠
–90°
3.18
∠
–90°
4.63
∠
–90°
Slope 2
A
0
∠
0°
0
∠
0°
0
∠
0°
0
∠
0°
Block
I
d
/
I
r
= 93.2%
< Slope 2 = 95%
B
0.315
∠
–90°
8.33
∠
–270°
7.77
∠
–270°
8.33
∠
–270°
C
0.315
∠
–270°
8.33
∠
–90°
7.77
∠
–90°
8.33
∠
–90°
Slope 2
A
0
∠
0°
0
∠
0°
0
∠
0°
0
∠
0°
Operate
I
d
/
I
r
= 96%
> Slope 2 = 95%
B
0.18
∠
–90°
8.33
∠
–270°
8
∠
–270°
8.33
∠
–270°
C
0.18
∠
–270°
8.33
∠
–90°
8
∠
–90°
8.33
∠
–90°
Summary of Contents for T35
Page 9: ...TABLE OF CONTENTS T35 TRANSFORMER PROTECTION SYSTEM INSTRUCTION MANUAL ix ABBREVIATIONS INDEX ...
Page 10: ...x T35 TRANSFORMER PROTECTION SYSTEM INSTRUCTION MANUAL TABLE OF CONTENTS ...
Page 472: ...5 270 T35 TRANSFORMER PROTECTION SYSTEM INSTRUCTION MANUAL TESTING CHAPTER 5 SETTINGS 5 ...
Page 596: ...iv T35 TRANSFORMER PROTECTION SYSTEM INSTRUCTION MANUAL ABBREVIATIONS ...