ABB RELION RET670 - Page 289

1 1
1
0.8 1 0.2 1
arg Re
L L M
L
V V
ArgDir ArgNeg s
I
× + ×
- < <
EQUATION1552 V2 EN-US (Equation 154)
For the AB element, the equation in forward direction is according to.
1 2 1 2
1 2
0.8 1 0.2 1
arg Re
L L L L M
L L
V V
ArgDir ArgNeg s
I
× + ×
- < <
EQUATION1553 V2 EN-US (Equation 155)
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
133.
V1
A
is positive sequence phase voltage in phase A
V1
AM
is positive sequence memorized phase voltage in phase A
I
A
is phase current in phase A
V1
AB
is voltage difference between phase A and B (B lagging 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 1
15 degrees
respectively (as shown in figure 133). It should not be changed unless system studies
have shown the necessity.
ZDRDIR gives binary coded directional information per measuring loop on the output
STDIRCND.
STDIR= FWD_A*1+FWD_B*2+FWD_C*4+FWD_AB*8+
+FWD_BC*16+FWD_CA*32+REV_A*64+REV_B*128+REV_C*256+
+REV_AB*512+REV_BC*1024+REV_CA*2048
1MRK 504 163-UUS A Section 8
Impedance protection
Transformer protection RET670 2.2 ANSI 283
Application manual