ABB Relion REG670, Руководство по применению

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A
B
C
IEC09000252_1_en.vsd
I
0
I
0
Z
0m
Z
0
-
Z
0m
Z
0
-
Z
0m
IEC09000252 V1 EN
Figure 102: Equivalent zero sequence impedance circuit for the double-circuit
line that operates with one circuit disconnected and earthed at both
ends
Here the equivalent zero-sequence impedance is equal to Z
0
-Z
0
m in parallel with (Z
0
-
Z
0m
)/Z
0
-Z
0m
+Z
0m
which is equal to equation 48 .
2 2
0
0
om
E
Z Z
Z
Z
-
=
EQUATION2002 V4 EN
(Equation 94)
The influence on the distance measurement will be a considerable overreach, which
must be considered when calculating the settings. It is recommended to use a separate
setting group for this operation condition since it will reduce the reach considerably
when the line is in operation.
All expressions below are proposed for practical use. They assume the value of zero
sequence, mutual resistance R
0m
equals to zero. They consider only the zero sequence,
mutual reactance X
0m
. Calculate the equivalent X
0E
and R
0E
zero sequence
parameters according to equation 49 and equation 50 for each particular line section
and use them for calculating the reach for the underreaching zone.
R R
X
R X
E
m
0 0
0
2
0
2
0
2
1 = ⋅ +
+








DOCUMENT11520-IMG3502 V2 EN
(Equation 95)
X X
X
R X
E
m
0 0
0
2
0
2
0
2
1 = ⋅ −
+








DOCUMENT11520-IMG3503 V2 EN
(Equation 96)
Section 8
1MRK 502 071-UEN -
Impedance protection
224 Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062
Application manual