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6.5.7.2
Directional residual current protection measuring 3I
0
·cos φ
φ is defined as the angle between the residual current 3I
0
and the reference voltage. Vref =
-3V
0
e
jRCADir
, that is -3V
0
rotated by the set characteristic angle
RCADir
(φ=ang(3I
0
)-
ang(V
ref
) ).
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
0
·cos φ gets larger than the set value.
-3V
0
=V
ref
3I
0
RCA = 0
°,
ROA = 90
°
= ang(3I
0
) - ang(3V
ref
)
3I
0
cos
en06000648_ansi.vsd
V
ref
ANSI06000648 V1 EN
Figure 44:
RCADir set to 0°
Section 6
1MRK 511 287-UUS A
Current protection
120
Technical manual
Содержание REC650 ANSI
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