Directional Overcurrent Protection, Phases
Stage with Definite-Time Characteristic Curve
Setting Values
Rotation angle of the reference voltage
-180° to +180°
Increments of 1°
Directional mode
Forward
Reverse
–
Method of measurement
Fundamental component
RMS value
–
Threshold value
51
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
Dropout ratio
0.90 to 0.99
Increments of 0.01
Time delay
0.00 s to 60.00 s
Increments of 0.01 s
Dropout 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)
Direction Determination
Type
With healthy voltages
With voltage memory 2 s
Forward range
V
ref,rot
±88°
Dropout differential forward/reverse range
1°
Directional sensitivity
Unlimited for 1 and 2-phase short circuits
Dynamically unlimited, stationary for 3-phase short
circuits
Approx. 13 V phase-to-phase
12.8
12.8.1
51
If you have selected the method of measurement = RMS value, do not set the threshold value under 0.1 l
rated,sec
.
Technical Data
12.8 Directional Overcurrent Protection, Phases
SIPROTEC 5, Merging Unit 6MU85, Manual
825
C53000-G5040-C074-1, Edition 01.2020