Siemens SIPROTEC 4 7UT6 Series Manual page 411

IfN Current at nominal frequency
Inf Current at n times the frequency (n = 3 oder 4)
[tdfrequenzeinf-trafo-7ut613, 1, en_GB]
Figure 4-4
Idiff Differential current = |Ι
INObj Nominal current of protected object
IXf Current at any frequency within specified range
Operating Times (Generators, Motors, Reactors)
7UT612
Pickup time / dropout time with single-side infeed
Pickup time at frequency
at 1.5 · setting Ι
at 1.5 · setting Ι
at 5 · setting Ι
Diff
Dropout time, approx.
Drop-off to pickup ratio
7UT613/63x
Pickup time / dropout time with single-side infeed
Pickup time at frequency
fast relays
> min
Ι
Diff
high-speed relays
fast relays
>> min
Ι
Diff
high-speed relays
Dropout time, approx.
Dropout ratio
SIPROTEC 4, 7UT6x, Manual
C53000-G1176-C230-5, Edition 09.2016
Frequency influence in transformer differential protection
+ Ι |
1 2
>
Diff
>>
Diff
>>
50 Hz 60 Hz
38 ms 35 ms
25 ms 22 ms
19 ms 17 ms
35 ms 30 ms
approx. 0.7
50 Hz 60 Hz
30 ms 27 ms
25 ms 22 ms
11 ms 11 ms
6 ms 6 ms
54 ms 46 ms
approx. 0.7
Technical Data
4.2 Differential Protection
16.7 Hz
78 ms
73 ms
20 ms
15 ms
150 ms
411