ABB Relion 670 series - Page 273

The calculated R
m
and X
m
values are updated each sample and compared with the set zone reach.
The adaptive tripping counter counts the number of permissive tripping results. This effectively
removes any influence of errors introduced by the capacitive voltage transformers or by other
factors.
The directional evaluations are performed simultaneously in both forward and reverse directions,
and in all six fault loops. Positive sequence voltage and a phase locked positive sequence memory
voltage are used as a reference. This ensures unlimited directional sensitivity for faults close to
the IED point.
7.6.6.5 Directional impedance element for quadrilateral characteristics
M16923-139 v6
The evaluation of the directionality takes place in Directional impedance quadrilateral function
ZDRDIR (21D). Equation
72 and equation 73 are used to classify that the fault is in forward
direction for phase-to-ground fault and phase-to-phase fault.
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 72)
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 73)
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 127.
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 115 degrees respectively
(as shown in figure
127). 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 502 066-UUS B Section 7
Impedance protection
267
Technical manual