ABB RELION 670 Series Applications Manual page 103

1MRK 511 364-UUS A
Observe a fact that these impedances can not be directly calculated from the maximum three-
phase short circuit currents for faults on the corresponding busbar. It is necessary to consider
separate contributions of different connected circuits.
The required data is as follows:
=
V 400
r
EQUATION1728 V1 EN-US
=
V
min
EQUATION1729 V1 EN-US
=
f 60
n
EQUATION1730 V1 EN-US
400
=
V
p
EQUATION1731 V1 EN-US
0.115
=
V
s
EQUATION1732 V1 EN-US
=
I
p
EQUATION1326 V1 EN-US
=
I 5
s
EQUATION1734 V1 EN-US
=
Z
L 1
EQUATION1328 V1 EN-US
=
Z
SA 1
EQUATION1329 V1 EN-US
=
Z
SB 1
EQUATION1330 V1 EN-US
S
max
EQUATION1331 V1 EN-US
(
j
cos
EQUATION1332 V1 EN-US
j
max
EQUATION1333 V1 EN-US
=
f
si
EQUATION1334 V1 EN-US
=
f
sc
EQUATION1335 V1 EN-US
Application manual
kV
380 kV
Hz
kV
3
kV
3
1200 A
A
( )
+ W
10.71 j 75.6
( )
+ W
1.15 j 43.5
( )
+ W
5.3 j 35.7
=
1000 MVA
)
=
0.95
max
= °
25
2.5 Hz
7.0 Hz
Rated system voltage
Minimum expected system voltage under critical system
conditions
Rated system frequency
Rated primary voltage of voltage protection transformers
used
Rated secondary voltage of voltage instrument
transformers used
Rated primary current of current protection transformers
used
Rated secondary current of current protection transformers
used
Line positive sequence impedance
Positive sequence source impedance behind A bus
Positive sequence source impedance behind B bus
Maximum expected load in direction from A to B (with
minimum system operating voltage V
Power factor at maximum line loading
Maximum expected load angle
Maximum possible initial frequency of power oscillation
Maximum possible consecutive frequency of power
oscillation
Impedance protection
)
min
Section 7
97