Capacitor fusing

[peterfkec]

Dear All,

Last week, I started a project installing additional capacitors and cap controllers in our 25kV system. After some research, we have noticed that some of our fuses that protect our existing caps have been blowing quite frequently. Is anyone aware of other fusing options that we can try?

 

[TurbineGen]

First you need to determine what is causing your capacitors to blow fuses. You might consider a current monitor of some sort. Fuses are very simple devices. They work on a heating curve. You might try one with a longer heating curve.

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If it is broken, fix it. If it isn't broken, I'll soon fix that.

 

[jghrist]

If the fuses are sized properly, and there are non-linear loads, you might have a harmonic resonance problem. Filters or a change in capacitor bank size might be needed.

 

[magoo2]

I would first start and see what fuse ratings are presently being used. Many manufacturers have changed the fusing schedules since there's much less dielectric fluid in modern capacitors and less chance of rupture. They have generally gone to higher fuse ratings for the same kvar ratings. Might check with Cooper and others. There's a chance your company is still using an older fusing table with smaller fuse sizes.

Also, are these primarily fixed or switched banks?

 

[peterfkec]

Thank you for the suggestions. Because we have no data on the faults, I am going to create a log to track the frequency. Harmonic resonance might be the culprit indeed. I will check into the fuse tables...

We are currently using fixed banks with only local control.