Functions
2.23 Auxiliary Functions
SIPROTEC, 7SJ62/64, Manual
C53000-G1140-C207-2, Release date 01.2008
349
2P-Procedure
Parameter
172
52 B.WEAR MONIT
can be set to activate the 2P procedure. An operating cycles diagram (see
sample diagram in the functional description of the 2P procedure), provided by the manufacturer, shows the
relationship of make-break operations and tripping current. The two vertices of this characteristic in a double
logarithmic scale are decisive for the setting of addresses
260
to
263
:
Point P1 is determined by the number of permitted make-break operations (parameter
261
OP.CYCLES AT
Ir
) for rated operational current
I
r (parameter
260
Ir-52
)
Point P2 is determined by the maximum number of make-break operations (parameter
263
OP.CYCLES Isc
)
for rated fault tripping current
I
sc (parameter
262
Isc-52
).
For the procedure to operate correctly, the time response of the circuit breaker must be specified in parameters
266
T 52 BREAKTIME
and
267
T 52 OPENING
.
I
2
t-Procedure
The
I
2
t-procedure is activated via configuration parameter
172
52 B.WEAR MONIT
. The square fault current
integrals are referred to the squared device nominal current. For purposes of determining the arc time, the
device must be informed of the CB tripping time
T 52 BREAKTIME
as well as the CB opening time
T 52
OPENING
of the circuit breaker. For recognition of the last zero crossing (arc deletion) of the currents after trip-
ping, the „Current-zero“ Criterion is required.
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