:: Home Page      
 Advertise your Business Here     
Browse  |   Placement Papers  |   Company  |   Code Snippets  |   Certifications  |   Visa Questions
Post Question  |   Post Answer  |   My Panel  |   Search  |   Articles  |   Topics  |   Errors
   Refer this Site  Refer This Site to Your Friends  Site Map  Contact Us      
Categories >> Engineering >> Electrical Engineering


why transmission line 11Kv OR 33KV,66Kv not in 10kv 20kv?
 Question Submitted By :: Electrical Engineering
  I also faced this Question!!      
Answer Posted By  
 Answers were Sorted based on User's Feedback
# 1
due to thhe form factor=1.11, so output voltage must be
mulipy of formfactor,so we get 11,22,33 

Is This Answer Correct ?    212 Yes 29 No
j.santosh ramana kumar
# 2
The answers mentioning the form factor 1.1 are correct.

Just one clarification...

1.1 is form factor of a Sine wave...hence ac voltage being
a sine wave holds Form Factor of 1.1 

Is This Answer Correct ?    64 Yes 17 No
pankaj rajput
# 3
form factor of alternating current is 1.1 not 1.11, which
is the ratio of rms value to average value of alternating generation of ac voltage is in multiple of 11,
like 11kv,33kv,44kv,66kv etc 

Is This Answer Correct ?    67 Yes 26 No
arindam mallick
# 4
it is because the form factor=1.11 so everything should be
multiple of 11.

Is This Answer Correct ?    76 Yes 36 No
# 5
First let us define form factor before we go into the

The form factor of an alternating current waveform (signal)
is the ratio of the RMS (Root Mean Square) value to the
average value (mathematical mean of absolute values of all
points on the waveform). In case of a sinusoidal wave, the
form factor is approximately 1.11.

The reason is some thing historical. In olden days when the
electricity becomes popular, the people had a misconception
that in the transmission line there would be a voltage loss
of around 10%. So in order to get 100 at the load point
they started sending 110 from supply side. This is the
reason. It has nothing to do with form factor (1.11).
Nowadays that thought has changed and we are using 400 V
instead of 440 V, or 230 V instead of 220 V.
Also alternators are now available with terminal voltages
from 10.5 kV to 15.5 kV so generation in multiples of 11
does not arise. 

Is This Answer Correct ?    31 Yes 3 No
# 6
FORM FACTOR of sine wave is 1.11
rms/avg=(im/root2)/(2*im/pi) = 1.11
FF of square wave is 1.00 n triangular is 1.15
so i think form factor is not the only logic behind
11kv/33kv but while the generator o/p formula suggest there
are certain terms multiplied with the form factor(1.11) n
it is forcibly made to a standadadised value by changing
certain parameters.. 

Is This Answer Correct ?    33 Yes 16 No
# 7
Above answers are not appropiately correct.Because we can
varry a voltage from 1kv to 132kv or 220kv. 

Is This Answer Correct ?    31 Yes 14 No
himansu sekhar behera
# 8
Pl. give me the right answar 

Is This Answer Correct ?    26 Yes 14 No
# 9
The Basic Idea behind a desired transmission voltage was still the form factor. In ancient times when we needed to use 10 kV at destination, simply multiplied the form factor to it Say 1.11X10=1.11 =11KV aprox.(we had taken 10% losses as standard thumb rule) similarily for 30 & 60 KV.

Form Factor = RMS voltage/Average Voltage For AC sine wave Form Factor is 1.11.

Now a days when, we have voltage correction systems, powerfactor improving capacitors, which can boost/correct volatge to desired level, we are using the exact voltages like 400KV inspite of 444KV. 

Is This Answer Correct ?    11 Yes 1 No
anurag agrawal
# 10
If it is so.. then where is 22kv,44kv,55kv,77kv 88kv, 99kv
why these voltages are not included in transmisson levels? 

Is This Answer Correct ?    10 Yes 0 No

Other Electrical Engineering Interview Questions
  Question Asked @ Answers
what are the protection equipments used betbeen HT line and transformer in a power plant   4
How many types of isolator is available for H.T.lines? which one is best for sub-station?   4
what is meant by lagging & leading current tata 1
In all electric motors, fans are provided to dissipate heat. How it dissipate the heat? By absorbing atmospheric air or by exhausting the heated air generated while running? ford 2
Why motor initial starting current is high? pennar 7
which turbine has high thermal efficiency a)open gas turbine b)close gas turbine   2
what is the suitable voltage of transmission line to transmit 10000w power through 250 km. (a)11kv (b)33kv (c)66kv (d)132kv ]and please tell me whats the logic behind it ongc 7
Which starter can be used for 3 phase verriable speed (2 stator wdg) induction motor ?   2
We have a 1275KVA existing Transformer in a power plant project. Customer want to get it test & confirm whether it is a Dyn1 Transformer or not. Pleae let me know how to test it. allied-group 1
can we start a 6.6kv ht motor with 415 lt supply   1
According to general circuit diagram of 1-Phase t/f , why the primary is not get short circuited ,even though the supply terminals both are directly connected through primary winding?   4
What are the consequences in using existing step up transformer (primary 6.6kv/175A, secondary 480v/2405A) for step down transformer to have a 6.6kv output?   1
For more Electrical Engineering Interview Questions Click Here