| 摘要 |
The invention relates to a method, a computer programme and a device ( 2 ) for determining contact wear in an electrical switchgear ( 3 ) in an electric switchgear assembly ( 1 ) as well as to a switchgear assembly ( 1 ) with such a device ( 2 ). According to invention, for determining a contact wear status variable (Cwsum) a current measuring signal (I<SUB>mess</SUB>) is monitored for deviations (Delta) from an expected faulty switch-off current (I<SUB>f</SUB>) and, in case of deviations, the status variable (Cwsum) is not immediately calculated from current measuring signal (I<SUB>mess</SUB>), but indirectly using a characteristic current value (I<SUB>char</SUB>). Embodiments, among other things, relate to: deviations by saturation of the current transformer ( 30 ) and maximal current measuring signal (I<SUB>max</SUB>) as characteristic current value (I<SUB>char</SUB>); status variable (Cwsum) as a measure for arcing power during switching-off and, in particular, equal to a potential function (f(I<SUB>mess</SUB>)) of the switch-off current (I<SUB>mess</SUB>). Advantages, among others, are: improved calculation of contact wear, improved condition based instead of periodic maintenance of switchgears ( 3 ), increased operational safety at reduced maintenance cost.
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