Functions
6-997SA522 Manual
C53000-G1176-C119-2
Inverse Time
Overcurrent
Stage 3I
0P
The logic of the inverse time stage in principle functions the same as the remaining
stages. The operate delay time in this case is however determined by the set charac-
teristic (Parameter /2*&XUYH), the magnitude of the earth current and the time mul-
tiplier ,S7LPH'LDO (Figure 6-58). A pre-selection of the optional characteristics
was already done during the configuration of the protection functions. Furthermore, an
additional fixed delay $GG7'(/$< may be selected. The optional characteristics
are listed in the technical data of Section 10.5 and 10.9.
Figure 6-58 shows the logic diagram. As an example, the setting addresses for the IEC
curves are shown in the diagram. The different setting addresses are referred to in
more detail in the setting information (Sub-section 6.5.2)
It is also possible to implement this stage as a further definite time stage. In this case
,S3,&.83 is the pick up threshold and $GG7'(/$< the definite time delay. The
inverse time characteristic is then effectively bypassed.
Figure 6-58 Logic diagram of the 3I
0P
–stage (inverse time overcurrent protection), for example IEC curves
Inverse Time Over-
current Stage with
Inverse Logarith-
mic Characteristic
The inverse logarithmic characteristic differs from the other inverse characteristics
mainly by the fact that the shape of the curve can be influenced by a number of pa-
rameters. The slope ,S7LPH'LDO and a time shift 7 ,3PD[ which directly af-
fect the curve, can be changed. The curves are listed in the technical date in Section
10.5.
The logic diagram is shown in Figure 6-59. In addition to the curve parameters, a min-
imum time ,S0LQ7'(/$< can be determined; below this time no tripping can oc-
cur. Below a current factor of ,S6WDUWSRLQW, which is set as a multiple of the
basic setting ,S3,&.83, no tripping can take place.
Further information regarding the effect of the various parameters can be found in the
setting information of the function parameters in Sub-section 6.5.2, refer also to Figure
6-63.
I
E
3I
0P
Yes
No
Reverse
Forward
Non-Directional
„1“
≥1
&
&
inrush-
stabilization
direction-
determination
forwards
reverse
&
&
Yes
No
,S627)7ULS
Yes
No
,S7HOHS%,
permissive
teleprot..
switch on
to fault
≥1
EF 3I0p TRIP
T0
627)7LPH'(/$<
&
&
PICKUP
PICKUP+DIRECT.
&
627)2S0RGH
t
3I
0
T0
1309 >EF BLOCK 3I0p
1357
EF 3I0p Pickup
1369
≥1
>EF Inst TRIP
$GG7'(/$<
,(&&XUYH
,S3,&.83
2SPRGH,S
,S,QUXVK%ON
3I0p Time Dial
Inactive
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