Transformer Question - Take Power in Any Direction

Yes It is feasible

thanks for your reply.

Is there any extra changes to be done while it is being constructed or any transformer can be used immediately when required.

-Vijay

How about OLTC to get fixed secondary voltage?.

Power =voltage x current you are wrong with your question its not power you mentioned.

Transformers do not "know" the direction of transformation, it's strictly a matter of winding ratios for inductive coupling. It makes no difference if it's an autotransformer or an isolation transformer. But there are plenty of issues to consider when back feeding a transformer, including the configuration of the windings, i.e. Delta or Wye (Star) and the appropriateness of switchgear, protective devices etc. etc.. Some of those issues don't exist for autotransformers, some do. it requires a thorough understanding of the application, the equipment and the people who will service it to make a decision.

ok but what abt the OLTC. How we will vary the voltage to get the constant output in primary side if we are back feeding it. If all the switchgears , equipment is made ready for the backfeeding, how about the voltage regulation. I seen in some of the OLTC stated that " This tapchanger is only to be used where power flow is from HV to LV"..

-Vijay

Current limiter...voltage in, voltage out...up to down, down to up...doesn't matter. Must limit current through the transformer to prevent runaway. If you don't the breaker, a.k.a. current limiter (on/off discriminator) will.

In normal operation HV to LV, the tap-changer will keep LV voltage at its rated value , say +/-1%. But if input is from LV winding, this voltage varies +/-5% or more - values above normal could overflux LV winding (regardless of tap-changer posn on HV winding - hence "caution" in specification).

You must specify to the transformer manufacturer what the use of the transformer will be, so that the OLTC is set up to regulate the output of the "load" side appropriately. Usually OLTCs are used with transformation from higher to lower voltage, to feed distribution or plant loads.

If transformation is from lower to higher voltage, OLTC is seldom (I can't say never, but I haven't seen it) used. Such transformation is usually found in generating plants to step up to transmission voltages, and the voltage from the generator is usually adjusted via the generator controls.

I do this regularly. Some of my generation is directly connected to a distribution bus. When the generator is not running, the transformer supplies the distribution load from the transmission line on the high side. When the generator is running, it supplies the load on the distribution bus. Any additional generated power is stepped up through the transformer and sent through the transmission system to other substations.

Why do you feel you need a constant voltage on the 132kV side? I would be very surprised if its constant right now. I suspect it varies throughout the day due to changes in loading and voltage drop on the 132kV source. If the 132kV side is connected to a multi-generator grid you will need some way to control VAR flow, but an OLTC would be a complicated and unreliable way to do so. The OLTC controls are not designed to operate in that direction. You should already have voltage controls on whatever generator or transformer would provide the 33kV power to the transformer. Use those controls to manage your voltage and VAR flow.