×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Harmonic Distortion Abbreviation

Harmonic Distortion Abbreviation

Harmonic Distortion Abbreviation

(OP)
I have an output from Dranview showing harmonic distortion in a three-phase system.  the system consists of motors fed from single phase drives, protected by breakers, and the breakers have been 'randomly' tripping.

My term in questions is VTHDRss.  There is a voltage vs time graph showing the Phase <A, B, C> Harmonic Timeplot, and the dots/lines that are plotted are labeled with that term.  I'm fairly certain that the 'VTHD' part refers to Voltage Total Harmonic Distortion, but am unsure what the Rss stands for.  Google only brought up a pdf in a foreign language( .no tag, Norway?) which is more or less an example of the output.

link to said pdf
http://www.bio.uib.no/internesider/Ombygg/Forprosjekt%20HIB%203%20og%204%20etg.pdf
Page 46, top graph on the page.

The only difference in the graphs seems to be a set up feature in the program, since my graph has only dots(compared to the example which has lines).  Further, where the two voltage sags occurred in the time frame, there are vertical lines on that graph.  I don't really know how to interpret the graph(since I don't know what VTHDRss is), but I'm hoping this term will clear it up a bit.  

Thank you.

RE: Harmonic Distortion Abbreviation

The Norwegians sometimes use the abbreviation Rss (middel) for RMS. It is English, actually. Root sum squared with (middle) meaning "mean". Same thing as Root Mean Squared or RMS.  

Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

RE: Harmonic Distortion Abbreviation

(OP)
Interesting.  Seems odd that they wouldn't just use RMS for the English version to avoid confusion.   

RE: Harmonic Distortion Abbreviation

Well - that's how it is.

What else would you suggest?

Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

RE: Harmonic Distortion Abbreviation

I came across rss a few years ago and had the same thoughts, (even though I'm an Englishman!)but I was wondering why the capital "R" and lower case ss at the time-an apparant emphasis on the word Root.
Regarding your comment about the single phase(input) VSD tripping your breakers. This will likely be the 3rd harmonic and is often solved by introducing a line reactor to the drive.
 

RE: Harmonic Distortion Abbreviation

THDR = the total harmonic distortion of the waveform as % of input Vrms (or Irms).
THDF = the same, but as % of fundamental.

But ss? My guess = steady state

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources