Answer / guest

because the form factor for ac is 1.1 so we keep the
transmitting voltages in multiples of 1.1

Answer / abubakar siddiq

normally generation voltage is 11kv . if we have to transmit
this power to large distance we must increase voltage and
decrease current to reduce I^2R losses so we increase the
voltage to 33kv if distance is not large and if distance is
very large 400kv , 500kv .. These are only standards by IEC ..
any other cab be used. but we use this bcoz standard
transformer , cables , insulators , arrestors for these
nominal voltages are available

Answer / dinakar

because form factor of sine wave is 1.1 form factor= rms
value /avg . So as all voltages are rms voltages they are
multiples of 1.1

Answer / prakash krishnappa

Hello

There is no rule to select in multiples of 11kV.
Way back in 1887, when the 1st AC transmission was made in
England, the sending end power station was designed for
10kV. At the receiving end, they witnessed close to 11kV
due to ferranti effect ( named of Engineer Sebastian Ziani
de Ferranti who designed the power station). This lead to
finding out the effect of capacitance on lightly or no load
overhead line on the receiving end voltage. Engineers then
started designing equipment for 11kV and perfected the
egineering design for a max of 12kV for 11kV system. This
is how 11kV was made as starting point. There after, the
Engineers started designing in multiples of 11kV ( no
particular rule though !). In US, you can see 7.5kV,
14.4kV, 161kV, 230kV , 345kV etc which are no where near
multiples of 11kV. Since English people were more daring
and liked travlling for business all over the world, they
took this 11kV( and its multiples) around the world and few
countries like US and some European countries did not take
this 11kV or multiples of 11kV.

Answer / muralichppl

what is the form factor of ac can you define it for this quation

Answer / rohit

it is because of form factor (1.11). form factor is rms value/ avg value. power generated from power stations is avg value. but when it is to be transmitted to distant place it has to be in rms. so in order to find relation between the generated power and transmitted voltage the form factor is considered. it can be further explained as in case of HVDC line the transmitted voltage is not multiple of 11. hence it explains.

Answer / manoj sharma

What is form factor dear guest...please define its
signifance....

Answer / engineer

form factor is not the cause..else we would have 9.9 kv line system also...so nothing to do with dat..its all about the transmission system equipments,whih are designed for the voltage levels of 6.6,11,33,66,etc

Answer / eng.tha&

in transmission We need to convert the Generating voltage
to Transmission voltage
because generating voltage has low voltage but high current
and we use a step up transformer after Generating unit to convert to high voltage and low current.
By reducing the current we get to minimize the losses at lines
since P=I^*R (R=Resistance of transmission line)
and the second benefit of decreasing the current by reducing the cross sectional area of cable (high current need high cross sectional area )i.e= reduce the cost
finally
at the Receiving end
we used a step down transformer to convert to low voltage and high current

we transmission electricity from on place to another with less losses and efficient method

Answer / kishore

IN INDIA GENERALLY FOLLOWED BRITISH RULE FOR IN CASE OF
ELECTRICITY.SO THAT ACCORDING 2 THAT ALL ELECTRICAL
EQUIPMENT ARE DESIGNED ARF THIS SPECIFIC RANGE LIKE
11KV,33KV,66KV ETC THATS WAY IF WE ARE JUST TRANSMIT
ANOTHER VOLTAGE LIKE 12KV,39KV ETC THEN ALL RESPECTIVE
EQUIPMENT ARE NOT AVALABLE IKE CONDUCTOR,T/FS,LA ETC.SO
THATS WAY WE JUST FOLLOW THAT METHOD FOR
TRANSMIT...............

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