EQUATION2002 V4 EN (Equation 111)
The influence on the distance measurement can 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 reduces 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 R0m equals to zero. They
consider only the zero-sequence, mutual reactance X0m. Calculate the equivalent X0E
and R0E zero-sequence parameters according to equation 112 and equation 113 for
each particular line section and use them for calculating the reach for the
underreaching zone.
2
0
0 0
2 2
0 0
1
m
E
X
R R
R X
æ ö
= · +
ç ÷
+
è ø
DOCUMENT11520-IMG3502 V1 EN (Equation 112)
2
0
0 0
2 2
0 0
1
m
E
X
X X
R X
æ ö
= · -
ç ÷
+
è ø
DOCUMENT11520-IMG3503 V1 EN (Equation 113)
Parallel line out of service and not grounded
Z0m
A
OPEN
21
21
en05000223_ansi.vsd
CLOSED
OPEN
CLOSED
B
ANSI05000223 V1 EN
Figure 68: Parallel line is out of service and not grounded
When the parallel line is out of service and not grounded, the zero sequence on that
line can only flow through the line admittance to the ground. The line admittance is
high which limits the zero sequence current on the parallel line to very low values. In
Section 3 1MRK504116-UUS C
IED application
200
Application manual
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