Setting Of Zones For Parallel Line Application - ABB RELION 670 Series Applications Manual

1MRK 504 152-UEN B
In many applications it might be necessary to consider the enlarging factor due to fault
current infeed from adjacent lines in the reverse direction in order to obtain certain sensitivity.
7.3.3.5

Setting of zones for parallel line application

Parallel line in service – Setting of zone 1
With reference to section
protected line.
However, influence of mutual impedance has to be taken into account.
Parallel line in service – setting of zone 2
Overreaching zones (in general, zones 2 and 3) must overreach the protected circuit in all
cases. The greatest reduction of a reach occurs in cases when both parallel circuits are in
service with a single phase-to-earth fault located at the end of a protected line. The equivalent
zero sequence impedance circuit for this case is equal to the one in figure
"Parallel line in
The components of the zero sequence impedance for the overreaching zones must be equal to
at least:
R =
0E
EQUATION553 V1 EN-US
X =
0E
EQUATION554 V1 EN-US
Check the reduction of a reach for the overreaching zones due to the effect of the zero
sequence mutual coupling. The reach is reduced for a factor:
= -
K 0 1
EQUATION1426 V1 EN-US
If the denominator in equation
imaginary part of the reach reduction factor for the overreaching zones can be written as:
( )
Re K 0
EQUATION1427 V2 EN-US
( )
Im K 0
EQUATION1428 V2 EN-US
Parallel line is out of service and earthed in both ends
Apply the same measures as in the case with a single set of setting parameters. This means
that an underreaching zone must not overreach the end of a protected circuit for the single
phase-to-earth faults.
Set the values of the corresponding zone (zero-sequence resistance and reactance) equal to:
Application manual
"Parallel line
service".
R + R
0 m0
X + X
0 m0
Z 0
m
× + +
2 Z 1 Z 0 R
f
( )
×
X m 0 Re B
= -
1
( ) ( )
2 2
+
Re B Im B
( )
×
X m 0 Im B
=
( ) ( )
2 2
+
Re B Im B
applications", the zone reach can be set to 85% of the
146 is called B and Z0m is simplified to X0m, then the real and
Section 7
Impedance protection
SEMOD55087-50 v2
SEMOD55087-52 v3
SEMOD55087-55 v4
113 in section
(Equation 144)
(Equation 145)
(Equation 146)
(Equation 147)
(Equation 148)
SEMOD55087-77 v3
213