GUID-74662396-1BAD-4AC2-ADB6-F4A8B3341860 V1 EN
Figure 67: Overcurrent protection of parallel operating transformers
Closed ring network topology
The closed ring network topology is used in applications where electricity distribution
for the consumers is secured during network fault situations. The power is fed at least
from two directions which means that the current direction can be varied. The time
grading between the network level stages is challenging without unnecessary delays
in the time settings. In this case, it is practical to use the directional overcurrent relays
to achieve a selective protection scheme. The way directional overcurrent functions
are used in closed ring applications can be illustrated. The arrows define the operating
direction of the directional functionality. The double arrows define the non-
directional functionality where faults can be detected in both directions.
Section 5 1MRS756378 D
Protection functions
142 REF615
Application Manual
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