Definite Time, Directional Time Overcurrent Elements 67-1, 67N-1 - Siemens 7SC80 Manual

pickup is reported OFF and the trip delay time is reset unless the threshold 50-2 PICKUP, 67-3 PICKUP or
50N-2 PICKUP, 67N-3 PICKUP has been exceeded again. If the threshold is exceeded again during the
dropout delay time, it is canceled. However, the trip command delay time 50-2 DELAY, 67-3 DELAY or
50N-2 DELAY, 67N-3 DELAY continues running. If the threshold value is exceeded after the expiry of this
time, the trip command is issued immediately. If the threshold value is not exceeded at that time, there is no
reaction. If the threshold value is exceeded again after the expiry of the trip command delay time and while
the dropout delay time is still running, tripping is initiated immediately.
Each of these elements can be directional or non-directional.
These elements can be blocked by the automatic reclosing function (79 AR).
The logic of the directional elements 67-2, 67-3, 67N-2 and 67N-3 corresponds to the logic of the 67-1
element shown in

Definite Time, Directional Time Overcurrent Elements 67-1, 67N-1

2.3.3
For each element, an individual pickup value 67-1 PICKUP or 67N-1 PICKUP is set which can be measured
as Fundamental or True RMS. Phase and ground currents are compared separately with the common
setting value 67-1 PICKUP or 67N-1 PICKUP. Currents above the setting values are recognized separately
when fault direction is equal to the configured direction. If the inrush restraint function is used, either the
normal pickup signals or the corresponding inrush signals are issued as long as inrush current is detected.
When the relevant delay times 67-1 DELAY, 67N-1 DELAY have expired, a tripping command is issued
unless an inrush has been recognized or inrush restraint is active. 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. Trip signals and other flags for each element are issued when the
element times out. The dropout value is roughly equal to 95 % of the pickup value for currents > 0.3 Ι
Pickup can be stabilized by setting dropout times 1518 67 T DROP-OUT or 1618 67N T DROP-OUT. This
time is started and maintains the pickup condition if the current falls below the threshold. Therefore, the func-
tion does not drop out at high speed. The trip-command delay time 50-1 DELAY or 50N-1 DELAY continues
in the meantime. After the dropout delay time has elapsed, the pickup is reported OFF and the trip delay time
is reset unless the threshold 50-1 PICKUP or 50N-1 PICKUP has been exceeded again. If the threshold is
exceeded again during the dropout delay time, the time is canceled. The trip-command delay time 50-1
DELAY or 50N-1 DELAY continues in the meantime. Should the threshold value be exceeded after its expiry,
the trip command is issued immediately. If the threshold value is not exceeded at this time, there will be no
reaction. If the threshold value is exceeded again after expiry of the trip-command delay time, while the
dropout delay time is still running, tripping occurs immediately.
The inrush current detection of the directional elements is disabled via settable dropout times if an inrush
current pickup occurs, because the presence of an inrush current does not constitute an intermittent fault.
Each of these elements can be directional or non-directional.
These elements can be blocked by the automatic reclosing function (AR).
The following figure shows by way of an example the logic diagram for the directional overcurrent element
67-1.
SIPROTEC Compact, 7SC80, Manual
E50417-G1140-C486-A8, Edition 07.2017
Figure 2-25.
2.3 Directional Overcurrent Protection 67, 67N
Functions
.
Nom
113