jX
R
X
C
Z
S
X
1
R
V
R
FW
R
RV
Z
S
en06000584-2.vsd
X
LLOC
X
1
F
W
X
C
X
line
- X
C
IEC06000584 V2 EN-US
Figure 118: Measured impedance at voltage inversion
Forward direction:
Where
X
LLoc
equals line reactance up to the series capacitor(in the picture
approximate 33% of XLine)
X1
is set to (XLindex-XC) · p/100.
p
is defined according to figure
1,2
is safety factor for fast operation of Zone 1
Compensated line with the series
capacitor not into the reach of zone 1. The
setting is thus:
X1
is set to (XLine-XC) · p/100.
When the calculation of XFw gives a negative value the zone 1 must be
permanently blocked.
For protection on non compensated lines facing series capacitor on next line. The setting is
thus:
•
X1 is set to (XLine-XC · K) · p/100.
•
K equals side infeed factor at next busbar.
Section 7
1MRK 505 343-UEN B
Impedance protection
184
Application manual
Summary of Contents for Relion 670 series
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