if we choose other freequency suppose 60hz ,our standara
freequency is 50hz.for transfer of power there must be same
freequency.Also if freequency increases number of poles
also increases,if poles inc.d diameter of equipment also
inc.it leads to high cost.
For a Electrical system to get synchronised, one of the
condition to get satisfy is the system frequency.
If frequency to be changed , then it is to be considered
right from power generation system.
While changing the frequency of the stationthe following
factors to be considered.
Frequency = 12o*poles/speed of the machine.
If this frequency factor to get change.....then pole of the
machine and the speed of the machine has to design
accordingly, which is quite inefficient and many factors to
be further considered.
The reason why in our country we are generating and
distributing the power with 50Hz/sec is, when frequency
increases say 60Hz/sec the losses in transmission and
distribution, transformers and active loads will be high.
economically 60Hz/Sec not affordable in our country.
because copper very high in cost.
in orfer to increase freq. wehave to increase the turbine
speed in power generating station. for that we need some
what more fuel(for diesel turbine) or water (for water
turbine). so it may lead coat effective.
It is a traditional system which has been established. all
the euipments are designed on the basis of 50 Hz so if we
change the freqency all the equipmets get damaged so we can
not change the frequency.
Yes we can use another frequency but for this change we have
to change in our power system such as
(1) As we know in generating stations the alternator is used
for producing electric energy and its frequency is given by
where Ns is synchronous speed and P is number of poles so
for increasing the frequency we have to increase the number
of poles which becomes very costly & so uneconomically
And another reason is that we used electrical instrument
which are standardized at 50 hz, 230 v
so we have to also change our electrical systems which are
also very costly
so this is only standard value we can change it but it is
how calculate external illumintion in a compound area. for
e.g. there is one open park having 600m2 area and i have to
put 40w flouresent tube fitting with pole. how shall i
calculate the numbers of fitting.
i have 28/32 MVA power transformer with 11/6.6 KC voltage
rating and 12%impedance.it have star connection at both
side.but it have another thied winding tertiary
winding.what is used of this winding.
pl tell me
the input mechanical power of a single alternator is
increased,its RPM increased but in case of an alternator
synchronised with grid its RPM does not increased with
increase of input mechanical power. why?