Undercurrent Protection
Setting Values
Method of measurement Fundamental component
RMS value
–
Threshold value I< 1 A @ 50 and 100 Irated 0.030 A to 35.000 A Increments of 0.001 A
5 A @ 50 and 100 Irated 0.15 A to 175.00 A Increments of 0.01 A
1 A @ 1.6 Irated 0.001 A to 1.600 A Increments of 0.001 A
5 A @ 1.6 Irated 0.005 A to 8.000 A Increments of 0.001 A
Time delay 0.00 s to 60.00 s Increments of 0.01 s
Dropout
The greater dropout differential (= | pickup value – dropout value |) 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 overcurrent and of 105 % for undercur-
rent functionality.
Minimum absolute dropout differential
Protection-class current transformer 15 mA sec. (I
rated
= 1 A) or
75 mA sec. (I
rated
= 5 A)
Instrument current transformer 0.5 mA sec. (I
rated
= 1 A) or
2.5 mA sec. (I
rated
= 5 A)
Times
Operate time
Approx. 25 ms + OOT
106
at 50 Hz
Approx. 22 ms + OOT at 60 Hz
Dropout time Approx. 25 ms + OOT at 50 Hz
Approx. 22 ms + OOT at 60 Hz
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 ≤ 80 Hz
Slightly expanded tolerances
f < 10 Hz
f > 80 Hz
Inactive
Tolerances
Currents, method of measurement = fundamental
component
1 % of setting value or 5 mA (I
rated
= 1 A)
or 25 mA (I
rated
= 5 A), (f
rated
± 10 %)
Currents, method of measurement = RMS value
(33 % portion harmonic, referring to fundamental component)
Up to 30th harmonic 1 % of setting value or 5 mA (I
rated
= 1 A)
or 25 mA (I
rated
= 5 A), (f
rated
± 10 %)
12.19
106
OOT (Output Operating Time): additional delay of the output medium used, for example, 5 ms with fast relays, see chapter Relay
Outputs
Technical Data
12.19 Undercurrent Protection
1486 SIPROTEC 5, Overcurrent Protection, Manual
C53000-G5040-C017-8, Edition 07.2017