Ι/Ι
p
= 1 to 1.94 Ι/Ι
p
= 2 to 4.75 Ι/Ι
p
= 5 to 7.75 Ι/Ι
p
= 8 to 20
1.44 1.94
The default setting of current values is ∞. They are, therefore, not enabled — and no pickup or tripping of
these protective functions will occur.
For specification of a tripping characteristic please note the following:
•
The value pairs are to be indicated in continuous order. You may also enter less than 20 value pairs. In
most cases, 10 value pairs would be sufficient to be able to define an exact characteristic. A value pair
which will not be used, has to be made invalid by entering ∞ for the threshold! Please ensure that a clear
and steady characteristic is formed by the value pairs.
•
For currents select the values from the above table and add the corresponding time values. Deviating
values Ι/Ι
p
are rounded to the next adjacent value. This, however, will not be indicated.
•
Currents smaller than the current value of the smallest characteristic point do not lead to a prolongation
of the tripping time. The pickup characteristic (see Figure 2-78, right side) goes parallel to the current
axis, up to the smallest characteristic point.
•
Currents greater than the current value of the largest characteristic point do not lead to a reduction of
the tripping time. The pickup characteristic (see Figure 2-78, right side) goes parallel to the current axis,
beginning with the largest characteristic point.
[ueb-anwenderkennl-020926-rei, 1, en_GB]
Figure 2-78 User-specified characteristic — example
For specification of a dropout characteristic please note the following:
•
For currents select the values from Table 2-8 and add the corresponding time values. Deviating values Ι/Ι
p
are rounded. This, however, will not be indicated.
•
Currents greater than the current value of the largest characteristic point do not lead to a prolongation of
the dropout time. The dropout characteristic (see Figure 2-78, left side) goes parallel to the current axis,
up to the largest characteristic point.
•
Currents smaller than the current value of the smallest characteristic point do not lead to a reduction of
the dropout time. The dropout characteristic (see Figure 2-78, left side) goes parallel to the current axis,
beginning with the smallest characteristic point.
•
Currents smaller than 0.05 · times the setting value of currents lead to an immediate dropout.
Table 2-8
Preferred values of standard currents for User-defined dropout characteristics
Ι/Ι
p
= 1 bis 0.86 Ι/Ι
p
= 0.84 bis 0.67 Ι/Ι
p
= 0.66 bis 0.38 Ι/Ι
p
= 0.34 bis 0.00
1.00 0.93 0.84 0.75 0.66 0.53 0.34 0.16
0.99 0.92 0.83 0.73 0.64 0.50 0.31 0.13
Functions
2.4 Time Overcurrent Protection for Phase and Residual Currents
SIPROTEC 4, 7UT6x, Manual 151
C53000-G1176-C230-5, Edition 09.2016
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