This variant has the possibility of choice between definite time delay and inverse time
delay.
The inverse time delay is defined as:
0 0
inv
0 0
kSN (3I 3U cos (reference))
t
3I 3U cos (measured)
× × × j
=
× × j
EQUATION1942 V2 EN (Equation 69)
Directional residual current protection measuring 3I
0
and φ
The function will operate if the residual current is larger than the set value and the
angle |φ = ang(3I
0
)-ang(U
ref
)| is within the sector RCADir ± ROADir
-3U
0
Operate area
3I
0
RCADir = 0º
ROADir = 80º
IEC06000652-3-en.vsd
IEC06000652 V3 EN
Figure 180: Example of characteristic
For trip, Residual current 3I
0
shall be larger than both INRel> and INDir>, and
residual voltage 3U
0
shall be larger than the UNRel>. In addition, the angle φ shall be
in the set area defined by ROADir and RCADir. Refer to the simplified logical diagram
in Figure
181.
Trip from this function can be blocked from the binary input BLKTRDIR.
When the function picks up, binary output signals START and STDIRIN are
activated. If the output signals START and STDIRIN remain active for the set delay
tDef the binary output signals TRIP and TRDIRIN get activated.
The function indicates forward/reverse direction to the fault. Reverse direction is
defined as φ is within the angle sector: RCADir + 180° ± ROADir
1MRK502052-UEN B Section 8
Current protection
397
Technical manual
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