Hi

Can anyone assist with some simple harmonics calculation software that will allow me to calculate the THDi and THDv at the PCC? I don't need anything too complicated as I am not designing a distribution network. I just need something simple where you enter the Xformer details, load details (% linear load, motor size, VSD characteristics etc), then it calculates Isc, THDi, THDv etc. at the PCC.

I have had a good look on the net but can't find anything suitable. There is quite a few software packages out their but they are either tied to a specific suppliers product or are unsuitable.

Any assistance would be greatly appreciated.

Thanks
Rotormtr

Software that tied to a specific supplier's product may be useful if you are working with similar products. VSDs that are of the same general design are very similar in the harmonics they produce.

ABB USA has an MS Excel spreadsheet that allows input for various VSD characteristics. I can't seem to get a link directly to the location, but if you go to abb-drives.com and click "main menu" then "products" then "documentation" you should get a list of product documentation. There is a place to select a specific product, but the Harmonic Analyzer Tool seems to be listed under "-14 Software" section for all of the products. For each VSD connected to the source, you need to put in an entry for input converter type and percent internal impedance (%Z). If you mouse over the heading for the items, you get pop-up instructions for the entries required in the cells below.

Hi Rotormtr, i have used the danfoss software many times and it is pretty good. It is based on their product but allows you to add non danfoss drives and input their impedance etc.


http://www.danfoss.com/BusinessAreas/Drive...are+Program.htm

Look for MCT 31 software.

Kens

One of the major poprblems is that each drive can have different input characteristics depending on whether it has AC line reactors, DC bus chokes or nothing, and if these components are used, then the sizing of them has a major impact on the results.
This is why, the programs tend to be for specific drives rather than generic.

Best regards,

Hi kens

Thanks for the lead. I downloaded the Danfoss program and seems to work well enough for what I want at this stage. Cheers.

rotormtr