ABB REG650 Technical Manual page 205

1MRK 502 043-UUS B
8.3.7.2
Technical Manual
Directional residual current protection measuring 3I
φ is defined as the angle between the residual current 3I
jRCADir
Vref = -3V e , that is -3V
0
(φ=ang(3I )-ang(V ) ). RCADir is normally set equal to 0 in a high impedance
0 ref
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
gets larger than the set value.
ANSI06000648 V1 EN
Figure 90: RCADir set to 0°
rotated by the set characteristic angle RCADir
0
V
RCA = 0°, ROA = 90°
ref
3I
0
= ang(3I ) - ang(3V
0 ref
3I cos
0
en06000648_ansi.vsd
Current protection
·cos φ
0
and the reference voltage.
0
)
-3V =V
0 ref
Section 8
·cos φ
0
199