Siemens SIPROTEC 4, User Manual

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[2p-richtungskoeffizient-300104-he, 1, en_US]
Figure 2-141 Value limitation of directional coefficient
With the characteristics description, you can calculate the actual remaining lifetime after each tripping.
[fo_7sj_remaining-lifetime _01, 1, en_US]
The index i characterizes the actual tripping. With the ratio of the maximum number of switching cycles (n
max
is n at
Ι
r
) to the actual calculated number of switching cycles, you get the ratio of these concerning the
maximum number of possible switching cycles in case of a tripping with rated operating current ( Ι
r
).
In the following example, the circuit breaker has tripped 100 times with rated operating current, 2 times with
rated short-circuit current, and 3 times with 10 kA.
The number of permissible trippings with rated operating current is calculated as following:
[fo_7sj_remaining-lifetime _03, 1, en_US]
RLT Remaining lifetime
In the example, 9465 more trippings with rated operating current are possible.
If the current criterion described in the Section “General” grants the phase-selective logic release, the present
number of operating cycles is calculated based on the tripping currents determined when the CB operating
time on tripping has elapsed. They are set off against the remaining lifetime allowing the present statistic
Functions
2.25 Auxiliary Functions
SIPROTEC 4, 7SJ62/64, Manual 325
C53000-G1140-C207-8, Edition 08.2016