Basler BE1-CDS220, Instruction Manual

Page: 473 / 476

BE1-CDS220 Settings Calculations D-15
I
A
+I
B
+I
C
=0
I
A
=-(I
B
+I
C
)
V
S
=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
S
=I
A
(R
W
+3R
L
+3R
R
)
V
T
=V
S
-R
W
I
A
V
T
=3I
A
(R
L
+R
R
)
Where:
I
A
=
3-Phase fault current
R
R
= Relay burden
R
L
= Lead burden
R
W
= Winding burden
SETTING NOTE 3 - PHASE-TO-PHASE FAULT, DELTA CONNECTED CTS
RELAY
2 I
I
3
2
1
I
2 I
I I
(0)
I
B
I
A
D2779-01
11-09-99
Figure D-9. Phase-To-Phase Fault, Delta Connected CTs