DOC. MIE91093 Rev. 1.34
Page 124 of 145
)
(
3
3
2
1
1
I
I
I
I
I
I
B
A
D
Therefore, applying current Iac only (from T1000 PLUS)
may result in a trip even when the current generated
by the D1000 is zero: you must increase D1000 current
until the relay contact drops out
If transformer Taps have to be taken into account, the
above formulas become a little more complex:
o
Restraint Current:
2
)
(
3
2
3
2
2
1
1
1
2
1
Tap
I
I
Tap
I
Tap
I
Tap
I
I
B
A
R
o
Differential Current:
2
2
1
1
1
2
1
)
(
3
3
Tap
I
I
Tap
I
Tap
I
Tap
I
I
B
A
D
1.15.8
Second harmonic restraint test
This test requires that you generate a distorted waveform:
The only way to generate such current waveform is to parallel
the main and auxiliary currents, having selected an 100 Hz
-1.5
-1
-0.5
0
0.5
1
1.5
0
0.005
0.01
0.015
0.02
0.025
50 Hz
2nd Harm
50 Hz + 2nd Harm
