Functions
2.3 Directional Overcurrent Protection 67, 67N
SIPROTEC, 7SJ62/64, Manual
C53000-G1140-C207-2, Release date 01.2008
98
The following table provides an overview of the interconnection to other functions of 7SJ62/64.
Table 2-6
Interconnection to other functions
2.3.2
Definite Time, Directional High-set Elements 67-2, 67N-2
For each element an individual pickup value
67-2 PICKUP
or
67N-2 PICKUP
is set, which can be measured
as
Fundamental
or
True RMS
. Phase and ground current are compared separately with the pickup values
of the
67-2 PICKUP
and
67N-2 PICKUP
relay elements. Currents above the setting values are signalled sep-
arately when fault direction is equal to the direction configured. After the appropriate delay times
67-2 DELAY
,
67N-2 DELAY
have elapsed, trip signals are issued which are available for each element. The dropout value
is approxmiately 95% of the pickup value for currents > 0.3
I
Nom
.
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 function
does not drop out at high speed. The trip-command delay time
50-2 DELAY
or
50N-2 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
50-2 PICKUP
or
50N-2 PICKUP
has been exceeded again. If the threshold is ex-
ceeded again during the dropout delay time, the time is cancelled. The trip-command delay time
50-2 DELAY
or
50N-2 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.
These elements can be blocked by the automatic reclosure feature (AR).
The following figure gives an example of the logic diagram for the high-set element 67-2.
Directional Time
Overcurrent Protec-
tion Elements
Connection to Auto-
matic Reclosing
Manual
CLOSE
Dynamic Cold Load
Pickup
Inrush Restraint
67-1
•
•
•
•
67-2
•
•
•
67-TOC
•
•
•
•
67N-1
•
•
•
•
67N-2
•
•
•
67N-TOC
•
•
•
•
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