[logikdia-ueberspgschutz-nullspg-wlk-310702, 1, en_GB]
Figure 2-28
Logic diagram of the overvoltage protection for zero sequence voltage
Freely selectable single-phase voltage
As the zero-sequence voltage stages operate separately and independently of the other protection overvoltage
functions, they can be used for any other single-phase voltage. Therefore the fourth voltage input U
4
of the
device must be assigned accordingly (also see Section 2.1.3 Power System Data 1 “Voltage Connection”).
The stages can be blocked via a binary input
>3U0>(>) BLK
. Internal blocking is not accomplished in this
application case.
Undervoltage protection
Undervoltage Phase-to-earth
Figure 2-29 depicts the logic diagram of the phase voltage stages. The fundamental component is numerically
filtered from each of the three measuring voltages so that harmonics or transient voltage peaks are largely
eliminated. Two threshold stages Uph-e< (address 3752) and Uph-e<< (address 3754) are compared with
the voltages. If the phase voltage falls below a threshold it is indicated in a phase-segregated way. Further-
2.5.2
Functions
2.5 Under and over-voltage protection (optional)
102 SIPROTEC 4, 7VK61, Manual
C53000-G1176-C159-5, Edition 05.2018
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