-3V
0
3I
0
RCA = -90°, ROA = 90°
= ang(3I
0
) – ang(V
ref
)
3I
0
cos
V
ref
en06000649_ansi.vsd
ANSI06000649 V1 EN
Figure 219: RCADir set to -90°
For trip, both the residual current 3I
0
·cos φ and the release voltage 3V
0
, must be larger
than the set levels: INCosPhiPU and VNRelPU.
Trip from this function can be blocked from the binary input BLKTRDIR.
When the function is activated binary output signals PICKUP and PUDIRIN are
activated. If the output signals are active after the set delay tDef the binary output
signals TRIP and TRDIRIN are activated. The trip from this sub-function has definite
time delay.
There is a possibility to increase the operate level for currents where the angle φ is
larger than a set value as shown in figure
220. This is equivalent to blocking of the
function if φ > ROADir. This option is used to handle angle error for the instrument
transformers.
1MRK505222-UUS C Section 7
Current protection
439
Technical reference manual
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