Functions
2.18 Auxiliary Functions
SIPROTEC, 7SK80, Manual
E50417-G1140-C344-A4, Release date 08.2010
252
Circuit Breaker Maintenance
Under address 172 52 B.WEAR MONIT one of the alternatives ΣI
x
procedure, 2P procedure, I
2
t procedure or
Disabled can be set. All parameters relevant to this function are available at parameter block P.System
Data 1 (see Section 2.1.3 ).
The following setting values are important input values the subfunctions require in order to operate correctly:
The CB Tripping Time
is a characteristic value provided by the manufacturer. It covers the entire tripping
process from the trip command (applying auxiliary power to the trip element of the circuit breaker) up to arc
extinction in all poles. The time is set at address 266 T 52 BREAKTIME.
The CB Operating Time
T 52 OPENING is equally a characteristic value of the circuit breaker. It covers the
time span between the trip command (applying auxiliary power to the trip element of the circuit breaker) and
separation of CB contacts in all poles. It is entered at address 267 T 52 OPENING.
The following diagram illustrates the relationship between these CB times.
Figure 2-97 Illustration of the CB times
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 functions (see
also margin heading „Current Flow Monitoring (CB)“ in Section 2.1.3.2.
Σ I Procedure
Being the basic function of summation current formation, the ΣI-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.
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