ABB Relion 670 Series Technical Reference Manual page 275

1MRK505222-UUS C
Technical reference manual
×
0.85 V A
- <
AngDir Ang
EQUATION1618 V1 EN
where:
AngDir
is the setting for the lower boundary of the forward directional characteristic, by default set to
15 (= -15 degrees) and
AngNegRes is the setting for the upper boundary of the forward directional characteristic, by default set
to 115 degrees, see figure 135.
V1 is positive sequence phase voltage in phase A
A
V1 is positive sequence memorized phase voltage in phase A
AM
I is phase current in phase A
A
The setting of AngDir and AngNegRes is by default set to 15 (= -15) and 115 degrees
respectively (see figure 135) and it should not be changed unless system studies have
shown the necessity.
ZDMRDIR (21D) gives a binary coded signal on the output STDIRCND depending on
the evaluation where FWD_A=1 adds 1, REV_A=1 adds 2, FWD_B=1 adds 4 etc.
X
ANSI05000722 V1 EN
Figure 135: Setting angles for discrimination of forward and reverse fault
+ ×
1 0.15 V AM 1
<
AngNeg
IA
AngNegRes
AngDir
R
en05000722_ansi.vsd
Section 6
Impedance protection
Re s
(Equation 49)
269