Functions
2.8 Earth Fault Protection in Earthed Systems (optional)
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
222
Figure 2-106 Logic diagram of the 3I
0P
stage for the inverse logarithmic characteristic
Zero-sequence voltage time protection (U
0
inverse)
The zero-sequence voltage time protection operates according to a voltage-dependent trip time characteristic.
It can be used instead of the time overcurrent stage with inverse time delay.
The voltage/time characteristic can be displaced in voltage direction by a constant voltage (U0inv. minimum,
valid for t āā) and in time direction by a constant time (T forw. (U0inv)). The characteristics are shown
in the Technical Data.
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