Answer / vamsi krishna

if it is depends on form factor then what abt 400kv and
750kv............

Answer / ravi

all voltages in rms values.thats y multiple of 11.
10kv avg. means :

rms value of 10kv(avg.) = 10k*form factor=11.1kvapprox=11kv
and similarly 400kv means avg. value = 400kv
and rms value = 440 kv

Answer / p.balaram

Presently 400Kv OH Lines are forming National Grid

Form factor applys at the time of Generation only

We can Step up or Step Down to any Voltage and transmitt

Answer / sadam hussain gaad

The miss concept is Line voltage is in multiple of 11 due
to Form Factor. 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 1.11.

The Main reason is something 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. Now a days when, we have voltage
correction systems, power factor improving capacitors,
which can boost/correct voltage to desired level, we are
using the exact voltages like 400KV in spite of 444KV

Answer / niraj talan

i think it is not related with form factor as many replied
because if so then why 400 kv or 765 kv is followed as
these r not multiple of 11.i think becuse of constrainst in
gen voltage that is between 10.5 to 15 kv we[earlier]to
choose 11 kv and 33 66 132 kv r multiple of 11 to suite
our transformation ratio.if once follewed it continuied
otherwise i dont find any reason that with 12 kv gen why v
cant have 44 144 kv transmission.

Answer / goud

all voltages in rms values.thats y multiple of 11.
10kv means 10kv in rms=10k*form factor=11.1kvapprox=11kv

Answer / naikulu

i think due to the add 10% as voltage drops for long
transmission line so we designed generating voltage 11,33
like that.instead of 10kv,33kv.

Answer / sripad

I'm not able 2 get one thing. What if the form factor is 1.1
or the transformer hassm 1.1*4 in its EMF eqn. Don't say dat
makes calculations easy. please tell me. I'm nt able to
understand

Answer / sandeep kumar sirka

actually it is related to form factor which is outcome of
rms to avg. value of alternating current.The value of form
factor is 1.1 . We use multiple of 11 in transmission
because of better efficiency in transmission voltage and
decreased flux leakage and less losses occurs in this
multiple 11 or form factor value that's why we use 11kv or
33kv or 66kv as a transmission voltage. And by no other
means the voltage is taken . Every thing depends on
efficiency and low cost transmission and minimum losses.

Answer / raghu

due to form factor

why the generator will take 8 to 12 hours to start after it got interrupted due to technical problems in case of power plants.

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