voltage and the current must lie between the blinders in second quadrant and fourth
quadrant. See figure
. Operation occurs if 90≤β≤270 and
ArgDir≤φ≤ArgNegRes
.
where
ArgDir
is the setting parameter for directional line in fourth quadrant in the directional element,
ZDMRDIR.
ArgNegRes
is the setting parameter for directional line in second quadrant in the directional element,
ZDMRDIR.
β
is calculated according to equation
The directional information is brought to the mho distance measurement from the mho
directional element as binary coded information to the input DIRCND. See
Directional impedance element for mho characteristic (ZDMRDIR) for information
about the mho directional element.
I
L1L2
jX
U
L1L2
f
ArgDir
I
L1L2
ArgNegRes
ZPP
en07000111.vsd
IEC07000111 V1 EN
Figure 68:
Simplified offset mho characteristic in forward direction for phase L1-
to-L2 fault
Offset mho, reverse direction
The operation area for offset mho in reverse direction is according to figure
. The
operation area in second quadrant is
ArgNegRes
+180°.
Operation occurs if 90≤β≤270 and 180° -
ArgDir ≤φ ≤ ArgNegRes
+ 180°
The β is derived according to equation
for the mho circle and φ is the angle between
the voltage and current.
1MRK502052-UEN B
Section 7
Impedance protection
187
Technical manual
Summary of Contents for Relion REG670
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