Previous in Forum: Neutral Wire Current   Next in Forum: Changing Motor On Air Compressor
Close
Close
Close
9 comments
Rate Comments: Nested
Participant

Join Date: Jan 2012
Posts: 2

High Voltage

01/25/2012 9:32 AM

for high voltage using 11kv,22kv,33kv why ?

Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

"Almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, vote them!
Guru

Join Date: Oct 2008
Posts: 42355
Good Answers: 1693
#1

Re: high voltage

01/25/2012 10:01 AM

What would you suggest?

Register to Reply
Guru
Engineering Fields - Electrical Engineering - Been there, done that. Engineering Fields - Control Engineering - New Member

Join Date: Dec 2008
Location: Long Island NY
Posts: 15600
Good Answers: 981
#2

Re: high voltage

01/25/2012 10:02 AM

Why not!

If you want a better explanation than that, you should explain your question better. For example, is this high voltage for power distribution, gas excitation, insulation testing, ion capture or another process?

__________________
"Don't disturb my circles." translation of Archimedes last words
Register to Reply
Member
India - Member - New Member

Join Date: Jan 2012
Posts: 9
#3

Re: high voltage

01/25/2012 10:15 AM

becuase when transmitting high voltage the rms{root mean square value} and peak factor comes into effect, then any value of voltage should be multiplied with 1.11avg value, thats why we will get voltage in 11 factor only...

Register to Reply
Guru

Join Date: Oct 2008
Posts: 42355
Good Answers: 1693
#4
In reply to #3

Re: high voltage

01/25/2012 10:24 AM
Register to Reply
Guru

Join Date: Apr 2009
Location: USA, Florida
Posts: 1595
Good Answers: 125
#5
In reply to #3

Re: high voltage

01/25/2012 3:50 PM

I can't believe you actually figured out what he was asking !

__________________
An obstacle is something you see when you take your eyes off the goal.
Register to Reply
Guru

Join Date: Oct 2008
Posts: 42355
Good Answers: 1693
#6
In reply to #3

Re: high voltage

01/25/2012 3:54 PM

Are you sure about that?

Register to Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 32175
Good Answers: 839
#8
In reply to #3

Re: high voltage

01/26/2012 5:30 AM

<sniff, sniff> Dog? No.... <sniff, sniff> Horse? No..... <sniff, sniff> Bull?

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 32175
Good Answers: 839
#7

Re: High Voltage

01/26/2012 5:25 AM

On Mars it is 12.2kV, 24.4kV and 36.6kV.

Actually, there have been loads of postings on this topic already, as a brief search has revealed:

http://cr4.globalspec.com/search/sitesearch?do=show&sort=textmatchrank&srch=why%2011kV&srchobjs=t%2Cc&fs=12&order=asc

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Guru

Join Date: Oct 2009
Posts: 2061
Good Answers: 169
#9

Re: High Voltage

01/26/2012 9:39 AM

Magic of the multiples of 11

by: K.Sivakumar, Manager - Training, Switchgear Training Centre, Larsen & Toubro Limited, Coonoor T.N.)

Foreword:The author has been coming across the following question repeatedly from the participants in his training programmes. Many other electrical professionals and electrical engineering students would also be having the same question in their minds, but only hesitant to ask anybody. An attempt is made here by the author to answer this question.

Question: Why Transmission, distribution and utilization voltages are in multiples of 11, as in 110V, 220V, 440V, 1.1kV, 3.3kV, 6.6kV, 11kV, 22kV, 33kV, 66kV, 110kV, 132kV & 220kV?

Answer: It is true only with respect to AC power systems. The first known man-made source of electricity is a cell, which is DC in nature. But, after realizing the disadvantages of the DC electric equipments, AC Electricity generating machines were invented. When these AC Machines were developed, the power of these machines was to be compared with the already available DC electricity, as it is human tendency to compare anything new with the existing ones. As in the case of steam engines.

When steam engines were invented, the power of the steam engines was compared with that of the horses, which were the power sources before the invention of the steam engine.

So, a value called RMS Value for AC Electricity was derived which compared the effectiveness of the AC Electricity with that of the DC Electricity. This value is the Effective Value of AC Electricity. As we were more interested in knowing the effect of AC electricity, all measuring instruments were and are designed to measure only the RMS value of AC electricity - may it be Voltage, Current, Power, etc.

But, for the designer sitting in the design lab, more than the effective value, the average value over a period on one sinusoidal cycle of AC Electricity was important. So, he designed an AC electric Generator, which would produce, on an average, a voltage over a period of one cycle, of say, 10kV (10 is a round figure, you know).

But, when this machine was built to the design and put to operation and when the output voltage was measured, it was found to be 11kV, as the meter was measuring NOT the average value but the effective or the RMS value. This relation existed for any voltage. So, a factor was arrived at - relating the RMS value and the average value, called Form Factor, which is the ratio of RMS value to the Average value, which for a sinusoidal wave form was about 1.1. Then, when the voltage was to be transformed, it was easy to have a whole number for the turns ratio of the transformer and hence all subsequent AC voltages became multiples of 11.

********

Register to Reply Score 1 for Good Answer
Register to Reply 9 comments

"Almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, vote them!
Copy to Clipboard

Users who posted comments:

electricalexpert65 (1); lyn (3); madhu sudhan (1); PWSlack (2); redfred (1); WJMFIRE (1)

Previous in Forum: Neutral Wire Current   Next in Forum: Changing Motor On Air Compressor

Advertisement