Siemens siprotec SJ62, Руководство пользователя

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2.3 Directional Overcurrent Protection 67, 67N
92
SIPROTEC 4, 7SJ62/63/64 Handbuch
C53000-G1140-C147-A, Edition 07.2015
2.3.3 Definite Time, Directional Overcurrent Elements 67-1, 67N-1
Phase and ground current are compared separately with the setting values
67-1
PICKUP
and
67N-1 PICKUP
of the respective relay elements. Currents above the
setting values are signalled separately when fault direction is equal to the direction
configured. If the inrush restraint feature is applied, either the normal pickup signals or
the corresponding inrush signals are output as long as inrush current is detected.
When, after pickup without inrush recognition, the relevant delay times
67-1 DELAY
,
67N-1 DELAY
have expired, a tripping command is issued. If the inrush restraint
feature is enabled, and an inrush condition exists, no tripping takes place, but a
message is recorded and displayed indicating when the overcurrent element time
delay elapses. Tripping signals and signals on the expiration of time delay are avail-
able separately for each element. The dropout value is roughly equal to 95% of the
pickup value for currents greater than > 0.3
I
Nom
.
In addition, pickups can be stabilized by setting dropout times
1518 67 T DROP-OUT
or
1618 67N T DROP-OUT
. This time is started if the current falls below the threshold
and maintains the pickup condition. The function thus does not drop out instanta-
neously. The trip delay time
67-1 DELAY
or
67N-1 DELAY
continues in the mean-
time. After the dropout delay time has elapsed, the pickup is reported OFF and the trip
delay time is reset unless the threshold
67-1 PICKUP
or
67N-1 PICKUP
has been
violated again. If the threshold is violated again while the dropout delay time is still run-
ning, it will be cancelled. The trip delay time
67-1 DELAY
or
67N-1 DELAY
continues
in the meantime. If the threshold is still exceeded after the time has elapsed, a trip will
be initiated immediately. If the threshold violation then no longer exists, there will be
no response. If the threshold is violated again after the trip command delay time has
elapsed and while the dropout delay time is still running, a trip will be initiated at once.
Pickup stabilization of the overcurrent elements
67-1
or
67N-1
by means of settable
dropout times is deactivated in the event of an inrush pickup, since an inrush is no in-
termittent fault.
These elements can be blocked by the automatic reclosure feature (AR).