Rated Duty Cycle of 15kV Vacuum Circuit Breakers 2

[SAMBOY]

Guys can you help me with this?

We have a plant expansion and we encountered this Rated Duty Cycle (sequence of operation) difference between the existing and the new 15kV Vacuum Circuit Breakers that we are using as follows:
a.) O-0.3s-CO-15s-CO
b.) O-0.3s-CO-3min-CO
c.) O-3min-CO-3min-CO

What is the significance and application of each sequence?
Can you please refer us also a website where we can have a technical paper or information regarding this subject?

Thanks in advance

 

[RalphChristie]

Samboy

This was discussed a while ago in:
thread238-135788

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[jghrist]

If you are using automatic reclosing with reclosing intervals smaller that the times in the rated duty cycle, you will have to derate the breakers.

If you are not using automatic reclosing, then the duty cycle is of no significance.