Siemens 7SC80 Manual page 370

Functions
2.26 Auxiliary Functions
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Figure 2-126
Current flow monitoring 212 BkrClosed I MIN, which some protective functions rely upon to detect a
closed CB, is used as the current zero criterion. It should be set with respect to the actually used device func-
tions (see also margin heading "Current Flow Monitoring (CB)" in Section
ΣΙProcedure
Being the basic function of summation current formation, the ΣΙ-procedure is always active and does not
require any additional settings. This is irrespective of the configuration in address 172 52 B.WEAR MONIT.
This method does not offer integrated threshold evaluation. The latter could, however, be implemented using
CFC.
ΣΙ x -Procedure
Parameter 172 52 B.WEAR MONIT can be set to activate the ΣΙ
the sum of all tripping current powers, the values are referred to the involuted CB rated operational current.
This value is indicated in the CB data at address 260 Ir-52 in the P.System Data 1 and can be set as
primary value. This reference allows the threshold of the ΣΙ
number of make-break operations. For a circuit breaker, whose contacts have not yet been worn, the
maximum number of make-break operations can be entered directly as threshold. The exponent for the invo-
lution of the rated operational current and of the tripping currents is set at address 264 Ix EXPONENT. To
meet different customer requirements, this exponent 264 Ix EXPONENT can be increased from 1.0 (default
setting = 2.0) to 3.0.
For the procedure to operate correctly, the time response of the circuit breaker must be specified in parame-
ters 2266 T 52 BREAKTIME and 267 T 52 OPENING.
The summated values can be interpreted as the number of tripping operations at rated operational current of
the CB. They are displayed in the statistical values without unit and with two decimal places.
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
370
Illustration of the CB times
2.1.3.2 Setting
x procedure. In order to facilitate evaluating
x procedure to correspond to the maximum
SIPROTEC Compact, 7SC80, Manual
E50417-G1140-C486-A8, Edition 07.2017
Notes.