# Why transmission voltages are multiples of 11?

Discussion in 'Electrical | Electronics | Communications' started by KARAD123, Jul 21, 2012.

Engineering Discipline:
Electrical
WHY ARE ALL THE VALUES OF VOLTAGES OF TRANSMISSIONS ARE IN MULTIPLES OF 11, MEANS 11KV, 33KV, 110KV, 220KV.? MY TEACHER ASKED US THIS QUESTION. PLZ HELP.

#1

Engineering Discipline:
Electrical
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#2
3. ### sree_23 Apprentice

Engineering Discipline:
Electrical & Electronics
why the transformers in transmission step up/down at the voltages which are multiples of 11..,like 33kv,66kv,121kv,etc?

#3

Engineering Discipline:
Electrical
5. ### pinank Rookie

Engineering Discipline:
Electrical & Electronics
its been a convention from olden days... there is no specific reason to it...

#5
6. ### Sparker Apprentice

Engineering Discipline:
Electrical
its not that it must be multiple of 11. Actually in olden day the used the multiple 1.1 i.e. formfactor for sine wave ,so that computation will be easier on design.its not 11 ,its 1.1 and its not compulsory.Infact not UHV,HVDC are not multiples of 1.1 .

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#6
7. ### sree_23 Apprentice

Engineering Discipline:
Electrical & Electronics
certainly thanks a lot frnds who have replied me with the apt answers..............

#7
8. ### Jeffrey Samuel Knight

Engineering Discipline:
Electronics
Nice to see your active involvement here. But a little of topic It will be even more better If you can avoid SMS language here in the forums

#8
9. ### ani the legend Newbie

Engineering Discipline:
Electrical & Electronics
depends on the form factor .... for a.c its 1.11

#9
10. ### sree_23 Apprentice

Engineering Discipline:
Electrical & Electronics
oh yeah i accept what you say....., i'll do so.....

#10
11. ### sree_23 Apprentice

Engineering Discipline:
Electrical & Electronics
oh yeah i accept what you say to avoid message language ....., i'll do so.....

#11
12. ### Akhilesh Garud Maniac

Engineering Discipline:
Electrical
is there any exact relation of its dependency on form factor?

#12
13. ### eris Apprentice

Engineering Discipline:
Electrical & Electronics
I hope it s dependent on RMS value n form factor. . Both r directly proportional to each other

#13
14. ### m.b Newbie

Engineering Discipline:
Electrical
please frnds try to answer it as I have been lukng for it for a long ago

#14
15. ### mallumatmari Apprentice

Engineering Discipline:
Electrical & Electronics
Only extra high voltage systems(super grids) have voltages in multiples of 11. I think because those transformers have 1:11 or 11:1 ratio. Simply guessed, don't know anything about that.

#15

Engineering Discipline:
Electrical
#16
17. ### Jeffrey Samuel Knight

Engineering Discipline:
Electronics
#17
18. ### shiv786 Newbie

Engineering Discipline:
Electronics & Communications
form facto is rms value upon avg. value
and value of form factor is 1.11 for transmission
so in my opinion that's the reason.....

#18
19. ### n.rajeev sharma Apprentice

Engineering Discipline:
Electrical & Electronics
it is due to form factor

#19