Tolerances for Stage Type Inverse Time-Undervoltage Protection
Voltages
0.5 % of the setting value or 0.05 V
Currents
1 % of the setting value or 5 mA (I
rated
= 1 A) or 25 mA (I
rated
= 5 A, f
rated
±
10 %), valid for protection-class current transformers
1 % of the setting value or 0.1 mA (I
rated
= 1.6 A) or 0.5 mA (I
rated
= 8 A,
f
rated
± 10 %), valid for instrument transformers
Operate time for 0 < V/V
Thresh
< 0.9
5 % of the setting value or 30 ms
Reset time delay
1 % of the setting value or 10 ms
Undervoltage Protection with Positive-Sequence Voltage
Setting Values
Threshold value
0.300 V to 200.000 V
Increments of 0.001 V
Time delay
0.00 s to 60.00 s
Increments of 0.01 s
Dropout ratio
1.01 to 1.20
Increments of 0.01
Current-flow criterion
On
Off
Threshold value I>
I
rated
= 1 A
0.030 A to 10.000 A
Increments of 0.001 A
I
rated
= 5 A
0.15 A to 50.00 A
Increments of 0.01 A
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 the overvoltage and of 105 % for the
undervoltage functionality.
Minimum absolute dropout differential
150 mV sec.
Times
Operate time with time delay = 0 ms, typical
Approx. 25 ms + OOT
66
at 50 Hz
Approx. 22 ms + OOT at 60 Hz
Operate time with time delay = 0 ms, maximum
Approx. 30 ms + OOT at 50 Hz
Approx. 26 ms + OOT at 60 Hz
Dropout time, typical
Approx. 25 ms + OOT
Dropout time, maximum
Approx. 30 ms + OOT
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, maintained;
Dropout of the pickup induced by blocking or by
increasing the measurand beyond the dropout
threshold
12.10.7
66
OOT (Output Operating Time): additional delay of the output medium used, see Chapter
Technical Data
12.10 Voltage Protection
SIPROTEC 5, Merging Unit 6MU85, Manual
841
C53000-G5040-C074-1, Edition 01.2020