FAQ power capacitors

Is the protection of capacitor banks standardized?

Partly. IEC 60 549 gives guidance HOW to protect, but does not advice WHAT current rating should be used. Recommendation lists of the fuse manufacturers are helpful.

What do I have to consider when selecting the proper fuse?

In order to take the harmonics and also the shock load at interruption into consideration, the current rating of the fuse should be two times the capacitor full load current. For safety reasons at interruptions with arcing reignitions the voltage rating should be a minimum of 50 % higher than the circuit voltage.

Is there any overload protection possible by the fuse-links in capacitor circuits?

No. Short circuit currents should be higher than 12 times the rated current.

Any questions?