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On Load Tap Changer Design Incorporates a Series Transformer
4

On Load Tap Changer Design Incorporates a Series Transformer

On Load Tap Changer Design Incorporates a Series Transformer

(OP)
Could someone explain how does a on-load tap changer work with a build-in series transformer? Does the series transformer help to reduce the arcing during the tap changing or work as a polarity switch?

Thanks!

RE: On Load Tap Changer Design Incorporates a Series Transformer

need more details about construction.  Have never seen the series transformer - transformer in series with transformer.  Normally OLTC will have switch which will reverse the direction of current flow after nominal tap there by reducing the extra amount of winding required.  Is it what you are talking about?  It looks like transformer when represented on drawings.  

RE: On Load Tap Changer Design Incorporates a Series Transformer

http://www.reinhausen.com/XparoDownload.ashx?raid=3924

Check out some information from the masters of the OLTC.

The Standard Handbook for EE (Fink and Beatty) has a good overview as well.

 

"An 'expert' is someone who has made every possible mistake in a very narrow field of study." -- Edward Teller

RE: On Load Tap Changer Design Incorporates a Series Transformer

(OP)
wow, that is really a very great article.
Thanks dpc!

NCTHAI - my guess the "series transformer" might be the reactance type LTC instead of a resistance type?!

RE: On Load Tap Changer Design Incorporates a Series Transformer

2
When the voltage or current of the winding in which the tap changer is to be fitted goes beyond the rating of the tap changer, then tappings can be made in a series transformer.This winding will be fed from the tertiary of main transformer.Secondary of the series transformer will be connected in series with the secondary of the main transformer to boost or buck the secondary voltage.

RE: On Load Tap Changer Design Incorporates a Series Transformer

(OP)
Thanks prc!
Is there a typical connection diagram available that shows the principle?

RE: On Load Tap Changer Design Incorporates a Series Transformer

Scopidia, Iam sorry Idont know how to load drgs to this site.You can see the connection diagrams in books on trfs or the book on Tap Changers Published by MR.You can also connection diagram see ANSI/IEEE std C57.131-1995 Requirements for Load tap changers -Page 35 Fig E.4(e).

With the development of high voltage and current OLTC, this scheme is rarely used nowadays except in US where OLTC is provided on LV side in some industrial trfs(Rectifier /arc furnace)

RE: On Load Tap Changer Design Incorporates a Series Transformer

(OP)
bacon4life
Thank you for the nameplate diagram. I am kind of scratching my head and trying to figure out what is the secondary load current flow path...maybe I need take a closer look on IEEE C57.131.

bacon4life, prc and dpc, if you guys could give me some heads up that would be a great help!

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