ABB Relion 650 Series Technical Manual page 121

1MRK 506 326-UUS B
I ·Z
A
-
ANSI09000121 V1 EN-US
Figure 63: Simplified offset mho characteristic and voltage vector for phase A-to-B fault
Operation occurs if 90≤β≤270.
Offset mho, forward direction
In the same way as for phase-to-phase fault, selection of forward direction of offset mho will
introduce an extra criterion for operation. Beside the basic criteria for offset mho according to
equation and 90≤β≤270, also the criteria that the angle φ between the voltage and the current
must lie between the blinders in second and fourth quadrant. See figure 64. Operation occurs if
90≤β≤270 and
where
ArgDir
ArgNegRes
β
Line distance protection REL650
Technical manual
I jX
AB·
V
A
I •
Z Rev
A
ArgDir ≤φ≤ ArgNegRes.
is the setting parameter for directional line in fourth quadrant in the directional
element, ZDNRDIR.
is the setting parameter for directional line in second quadrant in the directional
element, ZDNRDIR.
is calculated according to equation
© Copyright 2011 ABB Power Grids. All rights reserved
-
=
V I ·Z
Vcomp1
A A
ß
Vcomp2 = V
A
I
ANSI09000121-1-en.vsd
- (-
ZRev )
I
•
A
R
AB·
Section 5
Impedance protection
SEMOD154224-327 v3
115