Supply Voltage

It's to confuse you.

WHY ARE AC VOLTAGES IN MULTIPLES OF 1.1. eg. 11kV, 3.3kV, 220kV ...

Exactly. It's been discussed several times already.

Obviously because you only chose supply voltages that are multiples of 11.

I read it in one of the text books:

form factor of sinusoidal voltage is 1.11
since every avg. voltage multiplied by factor 1.11, high
voltage come in multiple of 11

However many people may not agree as transformers can convert to any voltage level,

I prefer to say AC voltage is generated in voltage levels in multiples of 11... rest all is upto us...

There is a factor for ac wave form. May be peak/ r.m.s i.e. 1.1. So all voltages are multiples of multiples of 1.1 or 11. If i remember correctly

Actually, it is 1.414 X peak= RMS.

or .707 X peak to peak=RMS

Which is just coincidence, me thinks!

Has nothing to do with turns ratio of transformer.

I'm surprised that no one here came up with the correct answer. The more exact question is: Why are these voltages used for distribution/supply of current? Initially the primary voltage was determined by the limitations of the materials and knowledge used to construct the first commercial dynamos. The 440v level was simply the best compromise. Once that was established the rest is easy. Each of the standard voltages is based on the need to keep the step-up/step down transformers easily manufacturable with adjustable taps! The addition of three phase current with star/delta configurations gives us the odd values we have today!

I almost forgot one thing. The line loss adjustment system for long runs allows for step-up in ten percent levels. This also contributes to the seemingly arbitrary voltages. (To my knowledge no one has used the line loss adj system in at least 80 years. It was originally designed for Edisons DC network!)

Not transformers. The compensation system for line losses was originally created for the Edison Electric Cos DC distribution systems. They used a peg board that allowed them to raise the voltage in ten pct steps to compensate for distance and load. When AC came into use they simply used the same wiring systems, substituting a tapped transformer for the peg board! No one would want to even attempt to rewire. I can't find a picture right now, but lets just say that saying it was a mess is an understatement! Ever been to Tijuana and looked at their distribution system? This was worse!!

The simple answer to such questions is:

It was original idea or thought for the time (every new idea starts from a raw and develope with time and experience). And the system which you see now is the work in field and labs of thousands people and investments.

I f ask a question like that it means you think that it is a product of a day.

Then unlimited question arise like:

Why:

Alphabets of your language were like that..

dress is like this

bicycle is like ..

sanitary fittings ???

Can anybody answer such questions?

Duplicate thread. This question has been raised several times already.