Answer / guest

transformer losses can be found by doing open circuit test
and short circuit test
open circuit test gives the core losses
short circuit test gives the copper losses
note in open circuit test the lv side is given supply and
in short circuit test the hv side is given supply

the iron losses can be reduced by providing laminations of
thinner dimension and using c.r.g.o sheet for laminations

the copper losses depend on the winding resistance which
increases due to heat can be reduced by providing
sufficient cooling to the winding.

Answer / manthesh.patil

we can check transformer losses by short ckt and open ckt test
,for checking cu loss we use short ckt test and for iron
loss we use open ckt test..to reduce copper loss we should
go for good cooling and for iron loss the core should be
perfectly laminated

Answer / sumitgarg

we can check a trans losses by open circuit and short
sircuit test.
to minimise these losses we shuold have a good cooling
system. apart from that all other points are related with
the insulation of the core,permitivity etc.

Answer / achala.g.s.

We can check like the following :
polarity, resistance and tap change operation tests should me made to check whether it has built correctly or not..


the ways to minimize it are:
*check of Oil quality.
*A check on the tap changer.

Answer / saravanan

oc and sc test helps to find the total losses means .oc test
gives the core loss .sc test gives the copper loss.if the
transformer is oil cooled means you must check the
conduction or breakdown test on the transformer oil. that
time only we can suggest the winding insulation loss

Three set (each phase contain 2 cable of 400 mmsq CU XLPE AWA) of single core cables are connected to 11 KV motor of 14 MW & the switch gear supplay is taken from 11kv feeder & this supplay taken from 275 KV substation. Problem is one pair cable(L3- 2 cable ) getting very hot & gland melted and damaged in switch gear side. the other two cable haven't any more hot(ambient temp only & L3 haveing 95- 100 Degree C. The same problem happened in 275 KV substation switch gear side also where the supply taken for 11 kv switch gear. But here L2 phese cable had problem. Why it is happening like this?. The cable having temperature different at different location from gland side inthe case of 11KV feeder of 275 kv substation. why ?

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