Answer / hareesh k soman

There r two reasons for the star and delta connection.. one
is load requirement i.e if load is un balanced we will go
for star.. i.e neutral will ground the fault current where
the delta will use for balanced load.
other reason is insulation requirement .. i.e in Power
transformer HV side will be star connected and LV side will
be delta connected. for example in 220kV/132kV power
transformer, in star connected HV line to line voltage is
220kV and phase voltage is 127kV i.e its required lesser
insulation. but in delta connected system V line= V phase
i.e 220kV insulation is required. but star only 127kV is
required...

Answer / tiang cs

HV system is mainly in connected in star connection because
of high insulation cost is needed for the HV system. If HV
connected in delta connection, and 1 phase shorted to
ground, then the phase voltage will become line voltage
which threathen the isulation in HV system.

Medium voltage usually connected in Delta connection
because no neutral is needed and if 1 phase shorted to
ground, the medium voltage system is unaffected and remain
operational.

For low voltage side, the connection is usually star
connection cause the neutral is needed for single phase
power supply. Besides that, LV system is most commonly
access by human and for safety reason, star connection is
prefered.

Answer / kidus mizan@yahoo.com

if the amount of power to be transformed is greater than that w/c can be handled by one transformer, it become necessary to employ two or more unit in parallel.

Answer / shahbaz shaikh

as we use the transformers for the step up or step down the
electrical quantity and when we use star/delta there is some
relation between line and phase quantity which help in the
connections

Answer / pavan kumar

the reason behind is to eliminate the triplen harmonics

Answer / rashid

As per question, we use delta /star or star /delta as per
our system requirment bcoz we need star connection to get a
nuetral and phase for our protections in case of delta we
are not able to do this, and otherwise the delta connection
is better for system stability also we also need star at
end users where we need single phase supply,

Answer / s p

Transformers are in such a way bcos they are either step up or step down. In case of Step down the configuration is Star to delta & the other way if it is Step up. It is to protect the transformer & the equipments safety.

Answer / sathish n p

Main purpose of using transformer is to convert the power,
Either from high to low or vice versa....i e step up or
Step down....for more deatils go through Power plant or
power system books.. Why transformer is neccessary in
transmission net work..n How the power will converted from
high voltage to low voltage..etc

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