Tapped Line Application - ABB RED650 Applications Manual

Section 7
Impedance protection
7.1.2.7
120
= × × +
Im( ) A X (2 R
0 1
EQUATION1286 V1 EN-US
The real component of the KU factor is equal to equation 49.
Re
( )
K = +
Re 1
u
( )

A
Re

EQUATION1287 V3 EN-US
The imaginary component of the same factor is equal to equation 50.
( )
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

A
IEC09000160 V3 EN-US
Figure 61: Example of tapped line with Auto transformer
+ × + × ×
R 3 R ) R (2 X
0 1 0
( )
⋅ 2
A X
m
0
2 2
( )
  
+ A
Im
  
× 2
m 0
( )
2
é ù
Im A
ë û
C
1MRK 505 393-UEN B
+
X )
1 0
GUID-740E8C46-45EE-4CE8-8718-9FAE658E9FCE v1
GUID-7AA566A4-B6E9-41A7-9927-4DAB50BE8D1A v1
B
BC
IEC09000160-3-en.vsd
Line differential protection RED650 2.2 IEC
Application manual
(Equation 48)
(Equation 49)
(Equation 50)