ABB RELION 670 Series Applications Manual page 190

Section 7
Impedance protection
IEC06000584 V2 EN-US
Figure 103: Measured impedance at voltage inversion
Forward direction:
Where
X
LLoc
X1
p
1,2
Compensated line with the series
capacitor not into the reach of zone 1. The
setting is thus:
X1
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.
•
184
jX
R
RV
X
LLOC
Z
Z
S S
X
C
When the calculation of XFw gives a negative value the zone 1 must be
permanently blocked.
X - X
line C
R
FW
en06000584-2.vsd
equals line reactance up to the series capacitor(in the picture
approximate 33% of XLine)
is set to (XLindex-XC) · p/100.
is defined according to figure
is safety factor for fast operation of Zone 1
is set to (XLine-XC) · p/100.
1MRK 504 152-UEN B
R
101
Application manual