Basler Electric BE1-87T - Manual (Page 130)

A-2 BE1-87T Setting Notes 9171300990 Rev V
Setting Note 2
I
A
+I
B
+I
C
=0
I
A
=-(I
B
+I
C
)
V=I
A
R
W
+(I
A
-I
C
)(R
L
+R
R
)-(I
B
-I
A
)(R
L
+R
R
)
=I
A
(R
W
+R
L
+R
R
+R
L
+R
R
)-I
B
(R
L
+R
R
)-I
C
(R
L
+R
R
)
=I
A
(R
W
+2R
L
+2R
R
)-(I
B
+I
C
)(R
L
+R
R
)
Since I
A
=-(I
B
+I
C
)
V=I
A
(R
W
+3R
L
+3R
R
)
Where:
I
A
= 3-Phase fault current
R
R
= Relay burden
R
L
= Lead burden
R
W
= Winding burden
Figure A-2. CT Burden-Delta Connected CTs 3-Phase Fault
B
A
D2751-17
01-30-98
R
W
V
R
W
I
A
I
B
I
C
C
R
W
R
W
R
L
I
C
- I
B
R
L
I
A
- I
C
R
L
I
B
- I
A
R
R
R
R
R
R