![background image](http://html1.mh-extra.com/html/abb/relion-670-series/relion-670-series_applications-manual_3052129323.webp)
7.12.3.5
Setting of zones for parallel line application
GUID-4E0C3824-41B6-410F-A10E-AB9C3BFE9B12 v1
Parallel line in service – Setting of zone 1
GUID-8A62367C-2636-4EC1-90FF-397A51F586F7 v1
, the zone reach can be set to 85% of the
protected line.
However, influence of mutual impedance has to be taken into account.
Parallel line in service – setting of zone 2
GUID-98D11A72-C5BE-4C67-ADB5-95124C2AF987 v1
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
in section
.
The components of the zero sequence impedance for the overreaching zones must be equal to
at least:
R
0E
R
0
R
m0
+
=
EQUATION553 V1 EN-US
(Equation 337)
X
0E
X
0
X
m0
+
=
EQUATION554 V1 EN-US
(Equation 338)
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:
0
0 1
2 1
0
m
f
Z
K
Z
Z
R
= -
×
+
+
EQUATION1426 V1 EN-US
(Equation 339)
If the denominator in equation
is called B and Z0m is simplified to X0m, then the real and
imaginary part of the reach reduction factor for the overreaching zones can be written as:
( )
( )
( )
( )
2
2
0
Re
Re
0
1
Re
Im
X m
B
K
B
B
×
= -
+
EQUATION1427 V2 EN-US
(Equation 340)
( )
( )
( )
( )
2
2
0
Im
Im
0
Re
Im
X m
B
K
B
B
×
=
+
EQUATION1428 V2 EN-US
(Equation 341)
Parallel line is out of service and earthed in both ends
GUID-345B36A6-B5FB-46DD-B5AE-81A1599FFC6E v1
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:
1MRK 505 343-UEN B
Section 7
Impedance protection
317
Application manual
Содержание Relion 670 series
Страница 1: ...RELION 670 SERIES Line differential protection RED670 Version 2 1 IEC Application manual...
Страница 2: ......
Страница 40: ...34...
Страница 64: ...58...
Страница 150: ...144...
Страница 406: ...400...
Страница 472: ...466...
Страница 494: ...488...
Страница 512: ...506...
Страница 524: ...518...
Страница 604: ...598...
Страница 686: ...680...
Страница 718: ...712...
Страница 722: ...716...
Страница 758: ...752...
Страница 759: ...753...