2.10 Directional earth fault protection
I0φ> (67N)
2 Protection functions
Technical description
88
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Figure 2.10-1. Block diagram of the directional earth fault stages I
0
> and
I
0
>>
Figure 2.10-2 Operation characteristic of the directional earth fault
protection in Res or Cap mode. Res mode can be used with compensated
networks and Cap mode is used with ungrounded networks.
Figure 2.10-3 Two example of operation characteristics of the directional
earth fault stages in sector mode. The drawn I
0
phasor in both figures is
inside the trip area. The angle offset and half sector size are user‘s
parameters.