ABB Relion 670 series, Руководство по применению

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Optional higher distance protection zones
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When some additional distance protection zones (zone 4, for example) are used they must be
set according to the influence of the series capacitor.
7.13.4.6 Setting of zones for parallel line application
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Parallel line in service – Setting of zone 1
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With reference to section "Parallel line applications" , 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
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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 205 .
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 405)
X
0E
X
0
X
m0
+ =
EQUATION554 V1 EN-US
(Equation 406)
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 407)
If the denominator in equation 407 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 408)
( )
( )
( ) ( )
2 2
0 Im
Im 0
Re Im
X m B
K
B B
×
=
+
EQUATION1428 V2 EN-US
(Equation 409)
Parallel line is out of service and earthed in both ends
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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.
Section 7 1MRK 505 343-UEN B
Impedance protection
358
Application manual