Previous in Forum: power cord-plug   Next in Forum: Fail Lamp Detection.
Close
Close
Close
7 comments
Active Contributor

Join Date: Jun 2008
Posts: 10

On load tap changer

06/03/2008 3:46 AM

I am a professional repairing more than 32 models of OLTCs made by various manufacturer eg MR, Elin, Trafo Union, ATL, Fuller, etc. Any one having problem with on load tap changers may please contact me.

I am in this field for 32 years.

Register to Reply
Pathfinder Tags: oltc
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Anonymous Poster
#1

Re: On load tap changer

06/03/2008 6:59 AM

Dear vs rathore

Please let me know your comments on connecting two HV transformers in parallel with different Tap settings. Is there any standard limit (IEEE or IEC) for the circulating current.

Thank you

Dr. Gaouda

Register to Reply
Anonymous Poster
#2
In reply to #1

Re: On load tap changer

06/12/2008 7:32 AM

Hi,

If two transformer are in parallel then the taps shall also be in the same position. An AVR shall be provided in the Transformer RTCC panel.

N.Suresh

Register to Reply
Anonymous Poster
#4
In reply to #1

Re: On load tap changer

01/26/2009 12:43 AM

When paralleling two transformers it is advisable (among other factors) that they should have the same tapchanger, otherwise circulating currents will be produce. Industry standard set this at 10% maximum.

Having the same characteristics and tapchanger brand, two transformers operated in parallel will not always be able to synchronize their voltages. This is because no two tapchangers even of the same brand and type will ever behave in the same way. That is why, the circulating current can not be totally eliminated but can only be mitigated.

In practice, we have paralleled power transformers several kilometers apart for a few hours without undesirable effects.

Register to Reply
Participant

Join Date: Aug 2009
Posts: 4
#5
In reply to #1

Re: On load tap changer

08/12/2009 12:42 AM

We are going to attempt to parallel 2x 30MVA transformers (1x 132kV, 22 step OLTC & 1x 138kV, 33 step OLTC) using Beckwith's M2001B "DeltaVAr 2" method.

Has anyone else been successful in getting this system to function properly?

Thank you.

__________________
GMK, P.S.E.
Register to Reply
Active Contributor

Join Date: Jun 2008
Posts: 10
#3

Re: On load tap changer

06/13/2008 1:56 AM

Dear Dr.,

I was busy with Merilli make tap changer repair.

Please note that transformer once paralled meeting all the condition of parallel operations, can make on load tap change with one step out in amongst them.

The OLTC controls block any further operations.

Transition resistance thermal with stand capability and Resisitor contact breaking capacity limits the amount of current handling capability. Load current plus/ minus circulating current all that matters during transition.

IEC 214 please may be refereeed to.

Regards,

VS Rathore

Register to Reply Off Topic (Score 5)
Anonymous Poster
#6

Re: On load tap changer

10/15/2009 9:56 AM

we have two oltc Mitsuhishi catalogo 1B-67047-C, we need change resistence and contact failure, were need found this parts?, these below to 2 tranformer 20 mva 115-13.8 kv, can you help us

thank you Henry / Venezuela

Register to Reply
Active Contributor

Join Date: Jun 2014
Posts: 15
#7

Re: On load tap changer

07/02/2014 7:49 AM

Dear Mr Rathore,

Its great to learn about your experience. We have a case where the existing 25 MVA transformer with 5 no of off-circuit taps positions. This needs to be retrofitted with OLTC having atleast > 11 steps sinoltage. Please suggestce we have frequent variations in I/C v

Register to Reply
Register to Reply 7 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Copy to Clipboard

Users who posted comments:

Anonymous Poster (4); PowerSys (1); srgovind (1); vs rathore (1)

Previous in Forum: power cord-plug   Next in Forum: Fail Lamp Detection.
You might be interested in: Taps, Bus Plugs, Flow Meters

Advertisement