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Generator with OLTC TX Parallell with Grid

11/03/2014 9:02 PM

11KV Generator is connected to step up transformer 11/33KV, this transformer is intended to be used for parallel operation with 33KV grid, would it be possible to use OLTC Tx for parallel operation with grid?

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Guru
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#1

Re: Generator with OLTC TX parallell with Grid

11/03/2014 9:19 PM

Correct me if I'm wrong but it sounds like you have a generator feeding a fixed tap transformer with the high-side connected to the grid, and you want to know if you can substitute a transformer with OLTC instead of the existing fixed tap transformer.

The answer is a qualified "yes", as long as you can figure out how to coordinate the generator AVR and the OLTC AVR, all other things being equal. It is much easier if the OLTC is manually controlled according to system conditions, just remember that there will be a step change in the generator output voltage every time the OLTC is operated.

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Guru

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#2

Re: Generator with OLTC TX Parallell with Grid

11/03/2014 9:40 PM

I fear that you are swimming upstream in a river of technology that you cannot overcome. Technical competence can't be acquired by asking strangers for advice and you are sure to be swept down stream to failure.

What, which, do I, would it be possible, is it, and I guess preface all of your requests for a lifeline to succeed at something which you are not equipped to accomplish.

Maybe some more course work in electronics/electrical theory is in order for you.

Good luck.

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Guru

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#3

Re: Generator with OLTC TX Parallell with Grid

11/04/2014 5:42 AM

You mean this will be synchronised to the grid?When you are coonecting to a grid a supply from generator why do u need a OLTC?

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Guru
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#6
In reply to #3

Re: Generator with OLTC TX Parallell with Grid

11/05/2014 11:06 AM

Dear Mr.nesubra,

Pl. see post no.5, a portion of it is as follows.

"OLTC is to be installed in the Transformer since your Transformer is to be put on GRID, by parallelling/synchronized operation, where the VOLTAGE will vary/fluctuate say 33 KV plus or minus 1 to 2 KV

Your Generator has to develope CONSTANAT voltage of 11 KV and hence to match the GRID Voltage 31 to 35 KV and your GENERATOR Voltage OF 11 kV the OLTC IS COMPULSORY for the Transformer."

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#4

Re: Generator with OLTC TX Parallell with Grid

11/05/2014 2:38 AM

For me I see no big difference unless otherwise there an usual assortment of information back the screen that u choose 2 mute..

Any CB can be used anywhere depends upon Technical specifications of generator and other bus Bus bar equipments...what matters most...Voltage class, quenching media type,cost,life span,operating cost and others electrical specs such as continously current (In),Making &breaking current,Instantaneous current, swift voltage, current wave etc plus pressure -temp-density variations of quenching materials must be Tested....

"Without devition from normal Progress is not Possible ""..

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Guru
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#7
In reply to #4

Re: Generator with OLTC TX Parallell with Grid

11/05/2014 11:21 AM

Dear Friend,

The original post calls for an answer - WHETHER OLTC IS REQUIRED or NOT.

Pl. enlighten how your STATEMENT WHICH READS as

"Any CB can be used anywhere depends upon Technical specifications of generator and other bus Bus bar equipments...what matters most...Voltage class, quenching media type,cost,life span,operating cost and others electrical specs such as continously current (In),Making &breaking current,Instantaneous current, swift voltage, current wave etc plus pressure -temp-density variations of quenching materials must be Tested.."

will answer for the original question.

DHAYANANDHAN.S

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Guru
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#5

Re: Generator with OLTC TX Parallell with Grid

11/05/2014 11:00 AM

Dear Mr.jackdaniel,

You have stated your Generator (11 KV) to be connected to GRID of 33 KV, hence the Ratio is 11/33 KV, in which there will be FLUCTUATION of VOLTAGE on 33 KV side.

OLTC is to be installed in the Transformer since your Transformer is to be put on GRID, by parallelling/synchronized operation, where the VOLTAGE will vary/fluctuate say 33 KV plus or minus 1 to 2 KV

Your Generator has to develope CONSTANAT voltage of 11 KV and hence to match the GRID Voltage 31 to 35 KV. and your GENERATOR Voltage OF 11 kV the OLTC IS COMPULSORY for the Transformer.

DHAYANANDHAN.S

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Power-User

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#8

Re: Generator with OLTC TX Parallell with Grid

11/05/2014 12:02 PM

"..would it be possible to use OLTC Tx for parallel operation with grid?" - Yes.

It is beneficial especially if the voltage of the grid is uncontrolled and the operator faces problem in matching the generator terminal voltage with that from grid in order to synchronise the machine.

Another situation the OLTC will come to the rescue of the operator is when there is a restriction (for whatsoever reason) on the generator VAR export and the grid is demanding VARs.

OLTC is a standard for large generator transformers in India as well as elsewhere in the world.

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#9

Re: Generator with OLTC TX Parallell with Grid

12/10/2014 10:45 PM

After final discussion with transformer's manufacturer , OLTC auto mode only can be used during Island mode or 100% powered up from the grid, there is no way for OLTC AVR to communicate with Generator AVR, Transformer AVR and Generator AVR will keep fighting each other in order to synchronize with Utility Grid. Suggestion from transformer's manufacturer:
OLTC in Auto mode during island mode(11kv to 33kv) condition or powered up by Utility (33kv to 11kv).
OLTC in manual mode/off mode during synchronization with Utility.
My opinion - OLTC is not necessary for this case.But we have purchased it.

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Guru
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#10

Re: Generator with OLTC TX Parallell with Grid

12/10/2014 11:31 PM

All is not lost, you have a unidirectional control for the tapchanger. You could swap it out for bidirectional controller that will know how to react with the changing VAR flow. See this thread http://cr4.globalspec.com/thread/98558/Uni-Directional-Bidirectional-on-Load-Tapchanger

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Anonymous Poster (1); dhayanandhan (3); jackdaniel (1); lyn (1); nesubra (1); raghun (1); RAMConsult (2)

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