ABB REG670 Applications Manual page 645

1MRK 502 071-UEN -
Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062
Application manual
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IEC12000623 V1 EN
Figure 312: An example for estimating the remaining life of a circuit breaker
Calculation for estimating the remaining life
The graph shows that there are 10000 possible operations at the rated operating current
and 900 operations at 10 kA and 50 operations at rated fault current. Therefore, if the
interrupted current is 10 kA, one operation is equivalent to 10000/900 = 11 operations
at the rated current. It is assumed that prior to tripping, the remaining life of a breaker
is 10000 operations. Remaining life calculation for three different interrupted current
conditions is explained below.
• Breaker interrupts at and below the rated operating current, that is, 2 kA, the
remaining life of the CB is decreased by 1 operation and therefore, 9999
operations remaining at the rated operating current.
• Breaker interrupts between rated operating current and rated fault current, that is,
10 kA, one operation at 10kA is equivalent to 10000/900 = 11 operations at the
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IEC12000623_1_en.vsd
Section 17
Monitoring
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