We use in star connection in seconday connection becouse
need neutal point in load sied( some load supply need 3
phase and some need single phase)but it is remember that
only star connection use in distrubution side transformer.
For distribution transformers, loads are connected to
secondry side. hence, requirement of neutral can be
obtained by connecting secondry of the transformer in star.
Secondly, to reduce or minimise the third harmonics in the
transformers, primary side connection generally done in
we should use delta connection in primary and star to
secondary because in delta line voltage = pphase voltage
and instar line voltage = 1.732phase voltage hence we get
173.2% more voltage hence we use delta star transformer.
in secondary side there is a chance for single phase load,
three phase load, if its single phase load added more there
is a chance for unequal voltage in each phases. here we
need one neutral point that is refered as a reference
potential for load equalise the phase voltages
WE USE DELTA CONNECTION AT PRIMARY AND STAR CONNECTION AT
SECONDARY IN CASE IF STEP UP OF VOLTAGE REQUIREMENT BECAUSE
IN DELTA/STAR TRANSFORMER THE OUT PUT VOLTAGE WILL BE 1.413
TIMES HIGHER THAN THE PHASE VOLTAGE EVEN WHEN BOTH HAVING
SAME NUMBER OF TURN. SO THE SECONDARY WILL REQUIRE LESS
Primary function of Distribution Transformer is to step-
down 33kv into 440v..while designing the transformer we
have to consider conductor size also...in delta side line
current=1.732 times phase current and in star side phase
current=line current...as we know current is directly
proportional to cross-section of the conductor..keeping in
mind about the cost factor of conductor on load side they
prefer star connection on load side..Guys i tried to
explain in different way..i agree with above answers
Generally we recevied power supply from HT.In HT side there
will be not available neutral source so in primery side we
given delta connection.But in secondary side we must need
nuetral for three phase & single phase equipments so we
will create from oueself (create from earthings) so here
the connection must be a star connection.
Can a transformer designed for a particular voltage and
frequency rating be used for different set of mentioned
ratings? Assume that the winding does not get burnt because
of overheating at higher voltage.
If yes, then under which constraint it is possible?