Tapped Line Application - ABB RELION 670 SERIES Applications Manual

Section 8
Impedance protection
8.1.2.7
170
(
1
× × +
2 Z Z
1 0 E
3
=
K
U
( )
1
× × +
2 Z Z
1 0
3
EQUATION1284 V1 EN
This means that the reach is reduced in reactive and resistive directions. If the real and
imaginary components of the constant A are equal to equation
= × × +
Re( ) A R 0 (2 R 1
EQUATION1285 V1 EN
= × × +
Im( ) A X (2 R
0 1
EQUATION1286 V1 EN
The real component of the KU factor is equal to equation 43.
( )
Re K 1
= +
u

Re

EQUATION1287 V3 EN
The imaginary component of the same factor is equal to equation 44.
( )
×
Im A X
( )
=
Im K
U
( )
2
é ù
+
Re A
ë û
EQUATION1288 V2 EN
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

)
+
R
Z
f
= -
1
(
× ×
Z 2 Z
+
R
1
0
f
+ × - ×
R 0 3 Rf ) X 0 ( 0 2 X
+ × + × ×
R 3 R ) R (2 X
0 1 0
( ) 2
Re A X
⋅
0
m
2 2
( ) ( )
  
Im
A A
+
  
2
m 0
( )
2
é ù
Im A
ë û
1MRK 506 369-UUS -
2
m 0
)
+ +
Z 3 R
0
f
41 and equation 42.
+ ×
X 1)
+
X )
1 0
Line distance protection REL670 2.2 ANSI
Application manual
(Equation 40)
(Equation 41)
(Equation 42)
(Equation 43)
(Equation 44)