Timer
If the detected fault direction is opposite to the set directional mode and GFC
release is active, BLK_EF output is activated once
Start delay time
has elapsed.
Reset timer is activated at the falling edge of General Fault Criterion release, that
is, when zero-sequence voltage falls below
Voltage start value
. BLK_EF is reset once
the reset delay time elapses. Activation of the BLOCK input deactivates the BLK_EF
output and resets Timer.
Figure 255: Activation of BLK_EF output (indication that fault is located opposite to
the set operate direction)
4.2.8.5 Application
MFADPSDE provides selective directional earth-fault protection for high-impedance
earthed networks, that is, for compensated, unearthed and high resistance earthed
systems. It can be applied for the earth-fault protection of overhead lines and
underground cables.
1MRS757644 H
Protection functions
620 series
Technical Manual
497
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