ABB Relion 670 series, Technical Reference Manual

Page: 212 / 1232

1
a g Re
ABM
AB
V
AngDir n AngNeg s
I
- < <
EQUATION2007 V2 EN
(Equation 23)
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 93 .
V1
AM
is positive sequence memorized phase voltage in phase A
I
A
is phase current in phase A
V1
ABM
is memorized voltage difference between phase A and B (B lagging A)
I
AB
is current difference between phase A and B (B lagging A)
The setting of AngDir and AngNegRes is by default set to 15 (= -15) and 115 degrees
respectively, see figure 93 , and it should not be changed unless system studies have
shown the necessity.
ZDSRDIR (21D) generates a binary coded signal on the output STDIR depending on
the evaluation where FWD_A=1 adds 1, REV_A=1 adds 2, FWD_B=1 adds 4.
R
X
AngDir
AngNegRes
en05000722_ansi.vsd
ANSI05000722 V1 EN
Figure 93: Setting angles for discrimination of forward and reverse fault
Section 6
1MRK505222-UUS C
Impedance protection
206
Technical reference manual