Why is the voltage in the generator(sub station) in multiples of eleven?

Question

In substations the voltage is a amultiple of eleven like 11v,132v.Why is that so?

Answer 1

Rural power electrification systems, in contrast to urban power systems, tend to use higher voltages because of the longer distances covered by those power distribution lines. 7200 volts is commonly used in the United States; 11kV and 33kV are common in the UK, New Zealand and Australia; 11kV and 22kV are common in South Africa. Other voltages are occasionally used in unusual situations or where a local utility simply has engineering practices that differ from the normal practices.In nut shell it is a the tradition and practice over the years which is also technically suitable and commercially available. One can designed the system with the amplitude of say 13 but components, parts will not be available commercially.

Answer 2

In the US, it's multiples of 12. As in 120v, 240v etc...... Did you just make this up?