Circuit-Breaker Maintenance - Siemens siprotec SJ62 User Manual

2 Functions

2.23.3.2 Circuit-Breaker Maintenance

General
Figure 2-116 Diagram of CB maintenance procedures
321
The procedures aiding in CB maintenance allow maintenance intervals of the CB
poles to be carried out when their actual degree of wear makes it necessary. Saving
on maintenance and servicing costs is one of the main benefits this functionality offers.
The universal CB maintenance accumulates the tripping currents of the trips initiated
by the protective functions and comprises the four following autonomous subfunc-
tions:
• Summation tripping current (ΣI-procedure)
• Summation of tripping powers (ΣI
• Two-point procedure for calculating the remaining lifetime (2P-procedure)
• Summation of all squared tripping current integrals (I
Measured value acquisition and preparation operates phase-selectively for all four
subfunctions. The three results are each evaluated using a threshold which is specific
for each procedure (see Figure 2-116).
Being a basic function, the ΣI-procedure is always enabled and active. The other pro-
x 2
cedures (ΣI , 2P and I
2
The I t-procedure is only implemented in the 7SJ64.
Current level and duration during the actual switching operation including arc extinc-
tion are crucial to the lifetime of the CB. Therefore, major importance is attached to the
x
-procedure)
t) can be selected by way of a shared configuration parameter.
2
t-procedure; only 7SJ64)
SIPROTEC 4, 7SJ62/63/64 Handbuch
C53000-G1140-C147-A, Edition 07.2015