Siemens Siprotec 5 7SS85 - Page 92

2nd Harmonic Detection Ground
Setting Values
Measured value IN measured
3I0 calculated
2nd harmonic content 10 % to 45 % Increments of 1 %
Times
Operating times Approx. 29 ms
Pickup
Harmonic: I
2nd harm
/I
1st harm
Setting value or at least
Protection-class current transformer I
1st harm
= 10 mA sec.
and I
2nd harm
= 10 mA sec. (I
rated
= 1 A)
I
1st harm
= 50 mA sec.
and I
2nd harm
= 50 mA sec. (I
rated
= 5 A)
Instrument transformers I
1st harm
= 1 mA sec.
and I
2nd harm
= 1 mA sec. (I
rated
= 1 A)
I
1st harm
= 5 mA sec.
and I
2nd harm
= 5 mA sec. (I
rated
= 5 A)
Dropout
The greater dropout differential (= | pickup threshold – dropout threshold |) of the following
2 criteria applies:
Dropout differential derived from the parameter
Dropout ratio
If this parameter is not available, a dropout ratio of 95 % applies for the overcurrent protection and a dropout
ratio of 105 % applies for the undercurrent protection.
Minimum absolute dropout differential
Protection-class current transformers 5 mA sec. (I
rated
= 1 A) or
25 mA sec. (I
rated
= 5 A)
Instrument transformers 0.5 mA sec. (I
rated
= 1 A) or
2.5 mA sec. (I
rated
= 5 A)
Harmonics: I
2nd harm
/I
1st harm
0.75 or
Protection-class current transformers I
2nd harm
= 5 mA sec. (I
rated
= 1 A) or
I
2nd harm
= 25 mA sec. (I
rated
= 5 A)
Instrument transformers I
2nd harm
= 0.5 mA sec. (I
rated
= 1 A) or
I
2nd harm
= 2.5 mA sec. (I
rated
= 5 A)
Frequency Operating Range
0.9 ≤ f/f
rated
≤ 1.1 According to specified tolerances
10 Hz ≤ f < 0.9 f
rated
1.1 f
rated
< f ≤ 90 Hz
Slightly expanded tolerances
f < 10 Hz
f > 90 Hz
Inactive
11.30
Technical Data
11.30 2nd Harmonic Detection Ground
SIPROTEC 5, Low-Impedance Busbar Protection, Manual 981
C53000-G5040-C019-C, Edition 04.2021