-3V
0
=V
ref
RCA = 0°
Operate area
Instrument
transformer
angle error
3I
0
(prim)
3I
0
(to prot)
a
Characteristic after
angle compensation
RCAcomp
en06000651_ansi.vsd
ANSI06000651 V1 EN
Figure 221: Explanation of RCAComp
Directional residual power protection measuring 3I
0
· 3V
0
· cos φ
φ is defined as the angle between the residual current 3I
0
and the reference voltage
compensated with the set characteristic angle RCADir (φ=ang(3I
0
)—ang(V
ref
) ). V
ref
=
-3V
0
e
-jRCA
. The function operates when 3I
0
· 3V
0
· cos φ gets larger than the set value.
For trip, both the residual power 3I
0
· 3V
0
· cos φ, the residual current 3I
0
and the
release voltage 3V
0
, shall be larger than the set levels (SN_PU, INRelPU 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 or after the inverse
time delay (setting TDSN) the binary output signals TRIP and TRDIRIN are activated.
The function shall indicate forward/reverse direction to the fault. Reverse direction is
defined as 3I
0
· 3V
0
·cos (φ + 180°) ³ the set value.
1MRK505222-UUS C Section 7
Current protection
441
Technical reference manual
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