Siemens siprotec 7SA6, Manual

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Functions
6-164
7SA6 Manual
C53000-G1176-C156-2
I>> Anr L1
Figure 6-91 Logic diagram of the I>>–stage
Definite Time
Overcurrent
Stage I> The logic of the overcurrent stage I> is the same as that of the I>>–stage. All referenc-
es to Iph>> must simply be replaced by
Iph>
and 3I0>> by
3I0>
. In all other respects
Figure 6-91 applies.
Inverse Time
Overcurrent
Stage I
p
The logic of the inverse overcurrent stage also in principal functions the same as the
remaining stages. The time delay in this case however results from the nature of the
set characteristic (parameter
IEC Curve
), the magnitude of the current and the time
multiplier (Figure 6-92). A pre-selection of the available characteristics was already
done during the configuration of the protection functions. Furthermore, an additional
constant time delay
T Ip Add
(address
2646
) may be selected, which are added to
the current dependant time derived from the IDMT characteristic. The available char-
acteristics are shown in the technical data, Section 10.5, Figure 10-1 to 10-3.
Figure 6-92 shows the logic diagram. The setting parameter addresses of the IEC
characteristics are shown by way of an example. In the setting information (Sub-sec-
tion 6.11.2) the different setting addresses are elaborated upon.
I>> Pickup L3
I>> Pickup L2
I>> Trip L3
I>> Trip L2
I
L3
I
L2
I
L1
Iph>
2610
&
T Iph>>
T 0
&
≥
1
2615
Yes
No
I>> SOTF
2614
Yes
No
I>> Telep/BI
Switch onto
fault
≥
1
further
stages
L3
L2
L1
3I0>>
&
T 0
&
≥
1
E
2613 T 3I0>> 2612
3I0>>
I
E
I>> Pickup L1
I>> Trip L1
I>> Trip E
I>> Pickup E
T 0
7104 >BLOCK O/C I>>
7110 >O/C InstTRIP
2680
SOTF Time DELAY
Iph>>
2611