![background image](http://html1.mh-extra.com/html/abb/relion-670-series/relion-670-series_applications-manual_3052129192.webp)
Parallel line in service – Setting of zone1
SEMOD168247-50 v2
"Parallel line application with mutual coupling"
set to 85% of protected line.
Parallel line in service – setting of zone2
SEMOD168247-53 v2
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
.
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 97)
X
0E
X
0
X
m0
+
=
EQUATION554 V1 EN-US
(Equation 98)
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 99)
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 100)
( )
( )
( )
( )
2
2
0
Im
Im
0
Re
Im
X m
B
K
B
B
×
=
+
EQUATION1428 V2 EN-US
(Equation 101)
Parallel line is out of service and earthed in both ends
SEMOD168247-69 v2
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:
R
0E
R
0
1
X
m0
2
R
0
2
X
0
2
+
--------------------------
+
è
ø
ç
÷
æ
ö
×
=
EQUATION561 V1 EN-US
(Equation 102)
Section 7
1MRK 505 343-UEN B
Impedance protection
186
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...