Harmonics prediction on an installation with variable speed drives.

I have been asked by a client to provide a harmonics prediction report on an installation with variable speed drives. I have never done one or been required to look into this before. Could someone assist me with the sort of information i would need.

We are installing around 15 Variable speed drives that will control numerous pumps and agitators around the process plant.  It is a brand new facility, so at the moment I don't know the nature of the supply to the facility although i will be able to find this out soon.

The variable speed drives will range from 0.37kW and 5.5kW, 3 Phase so nothing big.

I basically need to know what sort of information I would need to obtain from the client and the VSD manufacturer, and then how I would compile that information into a report.

I assume i will need to provide a report on each drive rather than an overall report for the installation.

Any help will be greatly appreciated.

  • Hi Joseph,

    Not sure I made any assumption in my response - I asked a question.  As far as i'm concerned there's no stigma or issue associated with  completing an assignment. 

    The reason i asked was because i was interested in where your predicted harmonic content values had come from.  Are these based on actual VSDs? 

  • Thank you for your response. actually from the sample presented, there is a catch statement i made in form of a note' Note: The exact current values will depend on the specific ratings and loads of each VSD.' so the predicted harmonic content were as a result of assumed harmonic values.

    CHEERS!!!