Tapped Line Application - ABB RELION 670 Series Applications Manual

1MRK 504 152-UEN B
( )
K
Re
EQUATION1287 V3 EN-US
The imaginary component of the same factor is equal to equation 138.
( )
Im K
U
EQUATION1288 V2 EN-US
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

IEC09000160 V3 EN-US
Figure 118: Example of tapped line with Auto transformer
This application gives rise to similar problem that was highlighted in section
from remote end"
example, for faults between the T point and B station the measured impedance at A and C will
be
Z =Z
A
DOCUMENT11524-IMG3509 V3 EN-US
Application manual
( )
A X
Re
= +
1
u
2
( )
 
A
Re
 
( )
× 2
Im A X
m 0
=
( ) ( )
2
é ù é
+
Re A Im A
ë û ë
A
, that is increased measured impedance due to fault current infeed. For
I + I
A C
+ ·Z
AT
TF
I
A
⋅ 2
m
0
2
( )
 
+ A
Im
 
2
ù
û
B
C
Impedance protection
(Equation 137)
(Equation 138)
BC
IEC09000160-3-en.vsd
"Fault infeed
(Equation 139)
Section 7
M17048-243 v3
M17048-245 v4
209