Switchyard

Well it depends on how many lines you will be switching.

A table can help.

It will also be necessary to know the gauge of the track.

Remember, if your not precise in your question on a public forum somebody will always misunderstand you.

Thanks for your reply sir,

I appreciate your suggestion.

well the details would be-

765kv switchyard, total generation 2*660 Mw for a thermal power plant

Draw it up on a computer with all the gear represented to scale and extrapolate from there.

A square grid laid over an aerial photograph works well. Simply count the squares that are more then 50% inside the switchyard area and multiply by the area of each square at the scale of the aerial photograph.