Where:
i No. of latest circuit-breaker switching cycle
Endur.
i
Residual switching cycles with rated normal current, after the ith
switching cycle
n
rated
Overall permissible switching cycles at rated normal current
n
trip
Overall permissible switching cycles at tripping current I
trip
n
rated
/n
trip
Lost switching cycles referring to rated normal current
EXAMPLE
For calculating the residual switching cycles of a circuit breaker, the following is assumed:
P1 (2.5 kA, 10 000)
P2 (50.0 kA, 50)
The circuit breaker has made 100 opening operations with rated normal current, 2 tripping operations with
rated short-circuit breaking current, and 3 tripping operations with 10 kA tripping current. Then, the residual
switching cycles with rated normal current are:
[FoCBW2P3-301012-01.tif, 1, en_US]
There are still 9465 possible break operations at rated normal current.
Circuit-Breaker Maintenance Warning
If the residual switching cycles of any phase lie below the threshold, a phase-selective warning signal is gener-
ated.
Application and Setting Notes
Parameter: Switching cycles at Ir
•
Default setting (_:101) Switching cycles at Ir = 10 000
You use the Switching cycles at Ir parameter to define the number of permitted switching cycles at
rated normal current.
You can find the information on the setting value in the technical data of the used circuit breaker.
Parameter: Rated short-circ.cur. Isc
•
Default setting (_:102) Rated short-circ.cur. Isc = 25 000 A
You use the Rated short-circ.cur. Isc parameter to define the rated short-circuit breaking current.
You can find the information on the setting value in the technical data of the used circuit breaker.
Parameter: Switching cycles at Isc
•
Default setting (_:103) Switching cycles at Isc = 50
You use the Switching cycles at Isc parameter to define the number of permitted switching cycles at
rated short-circuit breaking current.
You can find the information on the setting value in the technical data of the used circuit breaker.
9.6.5.2
Measured Values, Energy Values, and Supervision of the Primary System
9.6 Circuit-Breaker Wear Monitoring
1030 SIPROTEC 5, High-Voltage Bay Controller, Manual
C53000-G5040-C015-9, Edition 11.2017
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