44x/EN AP/Hb6
-140 MiCOM P40 Agile
• NOT I>: The direct current is higher than a fixed threshold equal to 2,5In.
• V<: All the voltages are lower than a V< threshold.
• NOT ∆Ι>: The line currents’ variation are higher than “Delta I” value.
• Detect 3P: setting that which allows the FFU three pole detection.
• Any pole dead: Cycle in progress.
• The I0 criterion (zero sequence current threshold) makes it possible to UNBLOCK
the distance protection in the event of phase-to-ground fault (if the fuse failure has
not yet been confirmed).
• The I2 criterion (negative sequence current threshold) makes it possible to
UNBLOCK the distance protection in the event of insulated phase to phase fault (if
the fuse failure has not been yet confirmed).
• The (V< AND /∆Ι) criterion makes it possible to detect the 3-pole Fuse Failure (no
phase voltage and no current variation) (no specific line energisation logic).
Fuse Failure detected =
(VN> AND “NOT I0>” AND “NOT I2>” AND “NOT I>”)
OR
(“Detect 3P” AND “NOT Any pole dead” AND V< AND “NOT ∆I”)
Figure 101: VTS logic
5.8.1.4 Fuse Failure Alarm reset
In the event of of a confirmed Fuse Failure, the condition which manages the reset is given
by (Figure 101):
Fuse Failure (reset) =
“No Fuse Failure detected”
AND “NO opto input energized”
AND “Healthy netwotk”
AND “NO All Pole dead”
where:
• “All Pole dead” means “All circuit breaker poles dead (breaker open 3 phase)”:
All Pole Dead =
“No current” AND “no voltage”
OR CB Opened ((52a) if assigned in PSL)
• Healthy Network =
“Rated Line voltage”
AND “No V0” AND “No I0”
AND “No start element” ∗
AND “No Power Swing”
∗ = no CVMR (no General Start Convergency).
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