Power generation

dear akhil

form factor for sinusoidal wave is 1.11

this may be one reason for your doubt

but for your kind information, in satluj jal vidyut nigam , the generating voltage level is 15 (lum sum like this) kv

so always 11 kv will be generating voltage it is not correct.

The question was about Power Lines Voltages in India.

It is interesting. What about other countries? China, Germany, Russia?

In USA you will find so many different voltages even a present tendency is to make small number of standard voltage levels.

I have seen: 13.8 kV, 138 kV as a 10 times ratio. I believe it is not a secret!

This because you inherited your supply voltages from the UK. It is to do with generator design and the costs involved in transformer and transmission lines the distance to the users load and the voltage drop that can be tollerated. It also governs the cable type used and its cost per unit length. If it is all over head it is easier to up the voltage, if its under ground 11 Kv is about the highest before special oil filled cables are needed to be used. Here in the UK the big electricity companies are even saving money by not using copper anymore preferring aluminium because it is 40% cheaper per meter. The transformers used to up the grid voltage use 10X voltage boost because it makes calculations easy.

The simple answer is money it governs most things in life.

My take, is that generation is 13.8 kv when you have 60 Hz, and 11.5 kv when you have 50 Hz. The same capacity machine will generate at those two different voltages with those two different frequencies. Now, I don't know what the frequency is in India, but that is my theory.

Here in Brazil usually power is generated in 13.8kV - 60Hz.

Some EU countries have 15 kV-50Hz,

In Africa you wikk find 20 kV

Both are so called Middle Voltages.

Several years ago I believe the max was somewhere 700 kV DC ( zero Hz!). Anybody knows of higher voltages used for transmission of el-energy?

The new international standard are using 400/132 kV transmission lines. This standarization of teh transmission volatage was required for the globale power/electrical networks connections between the countres i.e.in Euorop, North of Africa, Midle east countries, ....etc.