Functions
6-122 7SA6 Manual
C53000-G1176-C156-2
Definite Time Very
High Set Current
Stage 3I
0
>>>
The earth current I
E
=3I
0
is passedthrough a numerical filter and then compared with
the set value
3I0>>>. If this value is exceeded and alarm is issued. After the corre-
sponding delay times
T 3I0>>> have expired, a trip command is issued which is also
alarmed. The reset threshold is approximately 5 % + 0,5 mA below the pick-up thresh-
old.
The possibilities of selection are referred to in the heading “General”. Figure 6-69
shows the logic diagram of the 3I
0
>>>–stage. The function modules “direction deter-
mination”, “permissive teleprotection”, “switch onto fault”, and “inrush stabilization” are
common to all stages and described below. They may however affect each stage in-
dividually. This is done with the following parameters:
• Op. mode 3I0>>>, determines the operating direction of the stage: Forward,
Reverse or Non-Directional,
• 3I0>>> Telep/BI, determines whether a non-delayed trip with the teleprotection
scheme is possible (
Yes)ornotpossible(No),
• 3I0>>>SOTF-Trip, determines whether during energization of the feeder onto a
fault tripping with this stage shall be non-delayed (
Yes)ornot(No)and
• 3I0>>>InrushBlk, which is used to switch the inrush stabilization (rush blocking)
on (
Yes)oroff(No).
Figure 6-69 Logic diagram of the 3I
0
>>>–stage
Definite Time High
Set Current
Stage 3I
0
>>
Thelogicofthehighsetcurrentstage3I
0
>>isthesameasthatofthe3I
0
>>>–stage.
3I0>>> is therefore to be replaced by
3I0>>, then, Figure 6-69 also applies for 3I
0
>>.
Definite Time
Overcurrent
Stage 3I
0
>
The logic of the overcurrent stage 3I
0
> is the same as that of the 3I
0
>>>–stage.
3I0>>> is therefore replaced with
3I0>, then, Figure 6-69 also applies for 3I
0
>.
This stage operates with a specially optimized digital filter that completely suppresses
all harmonic components beginning with the 2nd harmonic. Therefore it is particularly
I
E
3I
0
>>>
Yes
No
Reverse
Forward
Non-Direct.
„1“
≥1
&
&
inrush-
stabilization
direction-
determination
forwards
reverse
&
&
Yes
No
3I0>>>SOTF-Trip
3113
Yes
No
permissive
teleprot..
switch onto
fault
≥1
EF 3I0>>> TRIP
T0
3173 TSOTF Time DELAY
3112
T0
&
&
PICKUP
PICKUP+DIRECT.
3172
&
SOTF Op. Mode
1305 >EF BLK 3I0>>>
3114
1354
EF 3I0>>>Pickup
1366
3I0>>>InrushBlk
3115
3110
3I0>>> Telep/BI
≥1
>EF Inst TRIP
3I0>>>
3111
T 3I0>>>
Op. mode 3I0>>>
Inactive
FNo1310
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