IAjX
VA
f
ArgDir
IA
ArgNegRes
IA·R
en 06000466_ansi. vsd
ANSI06000466 V1 EN-US
Figure 105: Simplified characteristic for offset mho in forward direction for A-to-ground fault
Offset mho, reverse direction
SEMOD154224-341 v4
In the same way as for offset in forward direction, the selection of offset mho in reverse direction
will introduce an extra criterion for operation compare to the normal offset mho. The extra is that
the angle between the fault voltage and the fault current shall lie between the blinders in second
and fourth quadrant. The operation area in second quadrant is limited by the blinder defined as
180° -
ArgDir
and in fourth quadrant
ArgNegRes
+180°, see figure 106.
The conditions for operation of offset mho in reverse direction for A-to-ground fault is 90≤β≤270
and 180°-
Argdir
≤φ≤
ArgNegRes
+180°.
The β is derived according to equation for the offset mho circle and φ is the angle between the
voltage and current.
Section 7 1MRK 502 066-UUS B
Impedance protection
230
Technical manual
To Next Page
Loading...
