ABB Relion 670 series - Page 431

Reactive Reach
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
Figure 222: 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
Fw
is set to (XLine-X
C
) · p/100.
X1
Rv
= max( 1.5 x (X
C
-X
LLOC
C);
X1
Fw
is defined according to figure 103
When the calculation of X1Fwgives a negative value the zone 1 must be
permanently blocked.
1MRK 506 369-UUS - Section 8
Impedance protection
Line distance protection REL670 2.2 ANSI 425
Application manual