Tapped Line Application - ABB RELION 650 Series Applications Manual

Section 7
Impedance protection
A
B
IEC09000255 V1 EN-US
Figure 62: Equivalent zero-sequence impedance circuit for a double-circuit line with one
The reduction of the reach is equal to equation 49.
=
K
U
EQUATION1284 V1 EN-US
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
EQUATION1285 V1 EN-US
Im( ) A
EQUATION1286 V1 EN-US
The real component of the KU factor is equal to equation 52.
( )
K
Re
u
EQUATION1287 V3 EN-US
The imaginary component of the same factor is equal to equation 53.
( )
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.
7.1.2.7

Tapped line application

112
-
Z Z
0 0m
I
0
Z
0m
-
Z Z
0 0m
IEC09000255_1_en.vsd
circuit disconnected and not earthed
( )
1
× × + +
2 Z Z R
1 0 E f
3
( )
1
× × + +
2 Z Z R
1 0 f
3
= × × + + ×
R 0 (2 R 1 R 0 3
= × × + + ×
X (2 R R 3
0 1 0
( )
A X ⋅
Re
= +
1
2
( )
  
A +
Re Im
  
( )
× 2
Im A X
m 0
=
( ) ( )
2
é ù é
+
Re A Im A
ë û ë
I
0
C
2
Z
= -
m 0
1
(
× × + +
Z 2 Z Z
1 0
0
- × + ×
Rf ) X 0 ( 0 2 X
+ × × +
R ) R (2 X X
1 0 1 0
2
m
0
2
( )

A

2
ù
û
)
3 R
f
50 and equation 51.
X 1)
)
GUID-740E8C46-45EE-4CE8-8718-9FAE658E9FCE v1
1MRK 505 363-UEN A
(Equation 49)
(Equation 50)
(Equation 51)
(Equation 52)
(Equation 53)
Application manual