Siemens SIPROTEC 7SD610 - 4.8 Backup Time Overcurrent Protection

Technical Data
4.8 Backup Time Overcurrent Protection
SIPROTEC, 7SD610, Manual
C53000-G1176-C145-6, Release date 02.2011
344
4.8 Backup Time Overcurrent Protection
Operating Modes
Characteristics
High-set Current Stages
As emergency overcurrent protection or back-up overcurrent protection
Backup time overcurrent protection Effective when the differential protection system is blocked (e.g. because of a failure
of the device communication)
Backup overcurrent protection operates independent of any events
Definite time stages (definite) I
Ph
>, 3I
0
>, I
Ph
>>, 3I
0
>>, I
Ph
>>>, 3I
0
>>>, I
Ph
>
ger
, 3I
0
>
ger
Inverse time stages (IDMT) I
P
, 3I
0P
; I
Pger
, 3I
0Pger
; one of the characteristics according to
4-2 to Figure 4-4 can be selected
Pickup value Iph>>
(phases)
for I
N
= 1 A 0.10 A to 25.00 A
or ∞ (ineffective)
Increment 0.01 A
for I
N
= 5 A 0.50 A to 125.00 A
or ∞ (ineffective)
Pickup value 3I0>> PICKUP
(earth)
for I
N
= 1 A 0.05 A to 25.00 A
or ∞ (ineffective)
Increment 0.01 A
for I
N
= 5 A 0.25 A to 125.00 A
or ∞ (ineffective)
Delay T Iph>>
(Phases)
0.00 s to 30.00 s
or ∞ (ineffective)
Increments 0.01 s
Delay T 3I0>>
(earth)
0.00 s to 30.00 s
or ∞ (ineffective)
Increments 0.01 s
Dropout ratio Approx. 0.93 for I/I
N
≥ 0,5
Pick-up times ca. 33 ms
Dropout times Approx. 30 ms
Tolerances Currents 3 % of setting value or 1 % nominal current
Times 1 % of setting value or 10 ms
The set times are pure delay times