ABB REL650 series Technical Manual page 174

Section 6
Impedance protection
168
V1A Positive sequence phase voltage in phase A
V1AM Positive sequence memorized phase voltage in phase A
IA Phase current in phase A
V1AB Voltage difference between phase A and B (B lagging A)
V1ABM Memorized voltage difference between phase A and B (B lagging A)
IAB Current difference between phase A and B (B lagging A)
The default settings for AngDir and AngNegRes are 15 (= -15) and 115 degrees
respectively (see figure 78
reverse fault for mho and quadrilateral characteristic) and they should not be changed
unless system studies show the necessity.
When Directional impedance element for mho characteristic
(ZDMRDIR) is used together with Fullscheme distance protection, mho
characteristic (ZMHPDIS) the following settings for parameter
DirEvalType is vital:
• alternative Comparator is strongly recommended
• alternative Imp/Comp should generally not be used
• alternative Impedance should not be used. This altenative is intended
for use together with Distance protection zone, quadrilateral
characteristic (ZMQPDIS)
X
Zset reach point
AngNegRes
-Zs
en06000416_ansi.vsd
ANSI06000416 V1 EN
Figure 78: Setting angles for discrimination of forward and reverse fault for mho
characteristic
and figure 79 Setting angles for discrimination of forward and
-AngDir
R
1MRK 506 335-UUS A
Technical manual