Tapped Line Application - ABB RELION 670 SERIES REG670 Applications Manual

Section 8
Impedance protection
8.2.2.7
214
( )
×
Im A X
( )
=
Im K
U
( )
2
é ù
+
Re A
ë û
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.

Tapped line application

ANSI05000224 V2 EN-US
Figure 90: Example of tapped line with Auto transformer
This application gives rise to similar problem that was highlighted in section
infeed from remote 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
Generator protection REG670 2.2 ANSI and Injection equipment REX060, REX061, REX062
2
m 0
( )
2
é ù
Im A
ë û
A
1MRK 502 071-UUS A
GUID-740E8C46-45EE-4CE8-8718-9FAE658E9FCE v1
GUID-7AA566A4-B6E9-41A7-9927-4DAB50BE8D1A v1
B
C
ANSI05000224-2-en.vsd
Application manual
(Equation 52)
BC
"Fault