ABB Relion 670 series - Tapped Line Application

( )
( )
( ) ( )
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 (Equation 311)
Ensure that the underreaching zones from both line ends will overlap a sufficient amount
(at least 10%) in the middle of the protected circuit.
8.12.2.7 Tapped line application
C
A
B
BC
ANSI05000224-2-en.vsd
ANSI05000224 V2 EN
Figure 181: Example of tapped line with Auto transformer
This application gives rise to similar problem that was highlighted in section "Influence
of fault current infeed from remote line end" , 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
Section 8 1MRK 506 369-UUS -
Impedance protection
370 Line distance protection REL670 2.2 ANSI
Application manual