ABB RES670 Technical Manual page 241

1MRK 511 408-UUS A
Phasor measurement unit RES670 2.2 ANSI
Technical manual
used for directionality and is defined as Vref = -3V
rotated by the set characteristic angle RCADir. RCADir is normally set equal to 0 in a
high impedance grounded network with a neutral point resistor as the active current
component is appearing out on the faulted feeder only. RCADir is set equal to -90° in
an isolated network as all currents are mainly capacitive. The function operates when
3I ·cos φ gets larger than the set value.
0
ANSI06000648 V1 EN-US
Figure 71: RCADir set to 0°
V
RCA = 0°, ROA = 90°
ref
3I
0
= ang(3I ) - ang(3V
0 ref
3I cos
0
en06000648_ansi.vsd
Current protection
—jRCADir
e , that is -3V
0
)
-3V =V
0 ref
Section 8
inversely
0
235