The inverse time delay is defined as:
t
TDSN I V reference
I V measured
inv
=
⋅ ⋅ ⋅
⋅ ⋅
( cos ( ))
cos ( )
3 3
3 3
0 0
0 0
ϕ
ϕ
EQUATION2032-ANSI V2 EN-US (Equation 133)
Directional residual current protection measuring 3I
0
and φ
SEMOD171963-48 v4
The function will operate if the residual current is larger than the set value and the angle |φ =
ang(3I
0
)-ang(V
ref
)| is within the sector
RCADir
±
ROADir
V
ref
=-3V
0
Operate area
3I
0
RCA = 0º
ROA = 80º
ANSI06000652-2-en.vsd
ANSI06000652 V2 EN-US
Figure 270: Example of characteristic
For trip, Residual current 3I
0
shall be larger than both
INRelPU
and
INDirPU
, and residual voltage
3V
0
shall be larger than the
VNRelPU
. In addition, the angle φ shall be in the set area defined by
ROADir
and
RCADir
. Refer to the simplified logical diagram in Figure 271.
Trip from this function can be blocked from the binary input BLKTRDIR.
When the function picks up, binary output signals PICKUP and PUDIRIN are activated. If the output
signals PICKUP and PUDIRIN 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
This variant has definite time delay.
Directional functions
SEMOD171963-60 v4
For all the directional functions there are directional pickup signals PUFW: fault in the forward
direction, and PUREV: fault in the reverse direction. Even if the directional function is set to
operate for faults in the forward direction, a fault in the reverse direction will give the pickup
Section 8 1MRK 502 066-UUS B
Current protection
514
Technical manual
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