Definite Time, High-set Elements 50-3, 50-2, 50N-3, 50N-2
For each element, an individual pickup value
50-3 PICKUP
,
50-2 PICKUP
or
50N-3 PICKUP
,
50N-2
PICKUP
is set. For
50-3 PICKUP
and
50N-3 PICKUP
, it is possible to measure the
Instantaneous
in
addition to
Fundamental
and
True RMS
. If set to
Instantaneous
, the element picks up at 2 · √2 · setting
value (rms). Each phase and ground current is compared separately per element with the common pickup
values
50-3 PICKUP
,
50-2 PICKUP
or
50N-3 PICKUP
,
50N-2 PICKUP
. If the respective pickup value is
exceeded, this is signaled. After the user-defined time delays
50-3 DELAY
,
50-2 DELAY
or
50N-3 DELAY
,
50N-2 DELAY
have elapsed, trip commands are issued which are available for each element. The dropout
value is roughly equal to 95% of the pickup value for currents > 0.3
Ι
Nom
. If the measurement of the instanta-
neous values has been parameterized for the 50-3 or 50N-3 element, the dropout ratio is set to 90 %.
Pickup can be stabilized by setting dropout times 1215
50 T DROP-OUT
or 1315
50N 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 delay time
50-3 DELAY
,
50-2 DELAY
or
50N-3 DELAY
,
50N-2 DELAY
continues running 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
50-3 PICKUP
,
50-2 PICKUP
or
50N-3
PICKUP
,
50N-2 PICKUP
has been exceeded again. If the threshold is exceeded again during the dropout
delay time, the time is canceled. The trip delay time
50-3 DELAY
,
50-2 DELAY
or
50N-3 DELAY
,
50N-2
DELAY
continues running in the meantime. If the threshold value is exceeded after this time has elapsed, the
trip command is issued immediately. If the threshold value is not exceeded at this time, there is 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 is initiated immediately.
These elements can be blocked by the automatic reclosing function (79 AR).
The following figures give an example of logic diagrams for the high-set elements
50-2 PICKUP
or
50N-2
PICKUP
. They also apply analogously to the high-set elements
50-3 PICKUP
and
50N-3 PICKUP
.
2.2.2
Functions
2.2 Overcurrent Protection 50, 51, 50N, 51N
58
SIPROTEC 4, 7SJ62/64, Manual
C53000-G1140-C207-8, Edition 08.2016
Summary of Contents for SIPROTEC 4
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