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Re
Re
Re
Im
K
A
X
A
A
u
m
( )
= +
( )
⋅
( )
+
( )
1
0
2
2
2
EQUATION1287 V3 EN-US
(Equation 143)
The imaginary component of the same factor is equal to equation
.
( )
( )
( )
( )
2
0
2
2
Im
Im
Re
Im
m
U
A X
K
A
A
×
=
+
é
ù
é
ù
ë
û
ë
û
EQUATION1288 V2 EN-US
(Equation 144)
Ensure that the underreaching zones from both line ends will overlap a sufficient amount (at
least 10%) in the middle of the protected circuit.
7.3.2.7
Tapped line application
M17048-243 v3
M17048-245 v4
C
B
BC
IEC09000160-3-en.vsd
A
IEC09000160 V3 EN-US
Figure 133: Example of tapped line with Auto transformer
This application gives rise to similar problem that was highlighted in section
, that is increased measured impedance due to fault current infeed. For
example, for faults between the T point and B station the measured impedance at A and C will
be
Z
A
=Z
AT
+ ·Z
TF
I
A
+ I
C
I
A
DOCUMENT11524-IMG3509 V3 EN-US
(Equation 145)
1MRK 505 343-UEN B
Section 7
Impedance protection
209
Application manual
Summary of Contents for Relion 670 series
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