ABB RELION 650 Series Applications Manual page 97

1MRK 505 363-UEN A
IEC05000534 V1 EN-US
Figure 46: Line differential protection with power transformer in protected zone
IEC05000444 V1 EN-US
Figure 47: System impedances
where:
Line data is
Transformer data is
Source impedance is
Application manual
(example showing 670 device)
Zsource 1
» =
Z X 15.0
L L
EQUATION1419 V1 EN-US
= Þ
X % 10%
EQUATION1420 V1 EN-US
=
Z 7.0
Source 1
EQUATION1421 V1 EN-US
= W Þ
Z 5
Source2 / 3
EQUATION1422 V1 EN-US
Z Z
L T
W
2
10 220
= × =
X 24.2
T 220
100 200
W
æ
220
=
(Z )
ç
Source2 / 3 220
è
70
Differential protection
Zsource 2/3
en05000444.vsd
W
2
ö
× = W
5 49.4
÷
ø
Section 6
91