Substation Related

You need to explain this better.

Are you proposing the supply the 220KV bus at 132KV?

The main effect on the transformers would be 6.6KV instead of 11KV

I'm confused!

what is the vector group of your transformer's and for which company are you working for in india?

The second question is irrelevant and possibly commercially and personally sensitive. It would be unusual to find a reply to it here and very unwise to post one.

I hope this is a temporary problem.You can lay 132 KV tee off line.But your transformers will not give 11KV..If cost is not factor and u want to start immediately and later on switch over to a regular line buy a 132KV/220KV auto Transformer which will be of sufficient capacity to to meet loads and cheaper.may be 40MVa open all other sections.At best u need buy i breaker ,Measuring CT and PT isolators.You can also lease this system and can result in tax savings

OK, so here are some obvious statements.....

This is a major, MAJOR change.

For one thing, a 220kV transformer won't work at 132kV to produce 11kV, unless you plan on going to the expense of adding 6.6kV/11kV step up transformers. If you think you can just change the 11kV transformer's tap changer to step up the output voltage from 6.6kV to 11kV you are (likely) going to be disappointed.

The other problems are that the bus-work, cables, or anything else related to transporting or measuring the current likely won't work within design safety tolerance parameters if you want to drop the voltage from 220kV to 132kV and also increase the current to get anywhere near the existing design output of the substation.

You can also add any VTs to the list of protection elements that need checking to ensure they will work within the required accuracies and tolerances when operating at the reduced voltage.

I suggest a detailed design review, study and plan for such a major change (which I am sure is what you and your project manager, asset owner, etc are doing).

By having a primary voltage of 132 KV in place of 220 KV will not only change the secondary voltage to 6.6 KV but will also reduce the KVA capacity of the transformer proportionately since the secondary current capacity will remain same at the original 11 KV level.

It would be worthwhile ( if you have already procured the transoformers) to study the possibility of installing an additional 132 kv / 220 KV transformer so that all the 220 KV arrangements will still remain utilized. Of course as already advised by a friend, this is a very major change and must be studied in detail to get the best practical solution.

Hire an appropriately-qualified local Electrical Engineering Consultancy to look at this, and delegate the design to that organisation.

Transformers can work. But, the secondary terminal voltage as well as the MVA rating will be lower by a Ratio: 220/132. I don't think this (especially the lower voltage on secondary side) will be acceptable for the system.

As I understand Jigu 1985 's problems is that he has a substation built for 220 KV while due to some problems the power that can be tapped from the nearest substation is at 132 KV. So, one possibility that could be evaluated is installing a transformer of 132 kv / 220 kv which will enable him to feed power from a 132 KV substation to his 220 kv substation keeping rest of the things as they are.Only an additional 132 KV bus system will be required in his substation. Or this transformer, if the things permit can be installed in the utility company's 132 KV substation.