2.3
Restricted Earth Fault Protection
The restricted earth fault protection detects earth faults in power transformers, shunt reactors, neutral
earthing transformers/reactors, or rotating machines, the starpoint of which is led to earth. It is also suitable
when a starpoint former is installed within a protected zone of a non-earthed power transformer. A precondi-
tion is that a current transformer is installed in the starpoint connection, i.e. between the starpoint and the
earthing electrode. The starpoint CT and the phase CTs define the limits of the protected zone exactly.
Restricted earth fault protection is not applicable to busbars.
7UT613/63x provides a second earth fault differential protection. The following function description refers to
the 1st instance (adresses 13xx). The 2nd instance is set via addresses 14xx.
Application Examples
2.3.1
Figure 2-52
to
Figure 2-58
[erddiff-sternwicklung-020926-rei, 1, en_GB]
Figure 2-52
[erddiff-1ph-transfor-020926-st, 1, en_GB]
Figure 2-53
SIPROTEC 4, 7UT6x, Manual
C53000-G1176-C230-5, Edition 09.2016
show some examples.
Restricted earth fault protection on an earthed transformer winding
Restricted earth fault protection on an earthed winding of a single-phase power transformer
Functions
2.3 Restricted Earth Fault Protection
125