Hitachi 670 Series Application Manual page 39

1MRK505382-UEN Rev. K
The circuit is protected by two terminals 1 and 2. These terminals process the same data except for
minor distortion in data that takes place during communication between them. Both terminals operate
as masters. If at least one of them indicates an internal fault, the protected circuit is disconnected.
IEC05000534 V2 EN-US
Figure 35:
IEC05000444 V2 EN-US
Figure 36:
where:
Line data is
Transformer data is
Source impedance is
Communication set-up, 670/650 series
Application Guide
Substation 1
CT 1
CB 1
IED 1
Current samples from terminal 1
Current samples from terminals 2 and 3
Line differential protection with a power transformer in the protected zone
Zsource 1
Circuit impedances
» =
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
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Analog and binary signal transfer for line differential protection
Line 50 km
220 kV, 600 A
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
Substation 2
CB 3
Yd1
CT 3
d
Y
CT 2
200 MVA,
220 / 70 kV,
CB 2
525 / 1650 A
IED 2
IEC05000534-2-en.vsdx
Zsource 2/3
IEC05000444-2-en.vsdx
W
2
ö
× = W
5 49.4
÷
ø
Section 4
33