Test Example 4 - GE T35 Instruction Manual

CHAPTER 8: COMMISSIONING
Test Phase Injected current
W1 current
Balanced A 0.25 ∠0°
Condition
B 0.5 ∠–180°
C 0.25 ∠0°
Min Pickup: A 0.25 ∠0°
change the Min
B 0.5 ∠–180°
PKP to 0.2 pu
C 0.25 ∠0°
Minimum A 0.25 ∠0°
Pickup
B 0.5 ∠–180°
C 0.25 ∠0°
Slope 1: A 0.25 ∠0°
return the Min
B 0.5 ∠–180°
PKP to 0.1 pu
C 0.25 ∠0°
Slope 1 A 0.25 ∠0°
B 0.5 ∠–180°
C 0.25 ∠0°
Intermediate A 2 ∠0°
Slope 1 & 2
B 4 ∠–180°
2 ∠0°
C
2 ∠0°
Intermediate A
Slope 1 & 2
4 ∠–180°
B
2 ∠0°
C
4 ∠0°
Slope 2 A
B 8 ∠–180°
C 4 ∠0°
Slope 2 A 4 ∠0°
B 8 ∠–180°
C 4 ∠0°

8.2.5 Test example 4

8.2.5.1 D/D0° transformer with phase b to c fault on the secondary delta winding
Transformer data — D/D0°, 20 MVA, 115/12.47 kv, CT1 (200:1), CT2 (1000:1)
T35 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
Displayed current
W2 current Differential
0 ∠0° 0 ∠0°
0.8 ∠0° 0 ∠0°
0.8 ∠–180° 0 ∠0°
0 ∠0° 0 ∠0°
0.95 ∠0° 0.154 ∠0°
0.95 ∠–180° 0.155 ∠0°
0 ∠0° 0 ∠0°
1.05 ∠0° 0.253 ∠0°
1.05 ∠–180° 0.255 ∠0°
0 ∠0° 0 ∠0°
0.92 ∠0° 0.123 ∠0°
0.92 ∠–180° 0.123 ∠0°
0 ∠0° 0 ∠0°
0.95 ∠0° 0.153 ∠0°
0.95 ∠–180° 0.153 ∠0°
0 ∠0° 0 ∠0°
1 ∠0° 5.37 ∠–180°
1 ∠–180° 5.37 ∠0°
0 ∠0° 0 ∠0°
0.8 ∠0° 5.57 ∠–180°
0.8 ∠–180° 5.57 ∠0°
0 ∠0° 0 ∠0°
0.8 ∠0° 11.93 ∠–180°
0.8 ∠–180° 11.93 ∠0°
0 ∠0° 0 ∠0°
0.6 ∠0° 12.13 ∠–180°
0.6 ∠–180° 12.13 ∠0°
DIFFERENTIAL CHARACTERISTIC TEST EXAMPLES
Status
Restraint
0 ∠0° Not Applicable
0.8 ∠0°
0.8 ∠–180°
0 ∠0° Block
I = 0.051 < Min PKP
d
0.948 ∠0°
0.950 ∠–180°
0 ∠0° Operate
I
= 0.102 > Min PKP
d
1.049 ∠0°
1.050 ∠–180°
0 ∠0° Block
I I
/ = 13.2%
d r
0.919 ∠0°
0.919 ∠–180°
0 ∠0° Operate
I I
/ = 15.9%
d r
0.948 ∠0°
0.948 ∠–180°
0 ∠0° Block
I I
/ = 84.3%
d r
6.37 ∠0°
< 86.6%
6.37 ∠–180°
0 ∠0°
Operate
I I
/ = 87.5%
d r
6.37 ∠0°
> 86.6%
6.37 ∠–180°
0 ∠0°
Block
I / I = 93.7%
d r
12.73 ∠0°
< Slope 2 = 95%
12.73 ∠–180°
0 ∠0° Operate
I / I = 95.7%
d r
12.73 ∠0°
> Slope 2 = 95%
12.73 ∠–180°
computed
computed
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