Abstract:
distribution transformers arc used to supply electric power to end users at the standard
secondary level voltage 380/220V AC. Healthy and optimal operation of these
transformers is crucial to the utility since most of the power generated at generating
stations has to pass through them for end use. Utilities always aim at achieving the most
economical alternative to deliver electricity, while maintaining the technical issues
related to reliability and security of supply . Proper sizing or distribution transfonncrs
plays an important role both in reducing costs and gaining efficient operation . Undersized
transformers suffer from r e liabi l ity p roblem s a n d r educed se rv ice life . C on v ersely ,
oversiz e d tr a n sfo r mers add e x cessive capital costs and extra energy losses re s u l tin g lrorn
high no -l o ad los s es. With continuou s incre a s e i n the nat io na l elec tri c al e n e r g y
consumption. t he r e i s a requirement for improved and efficient operat i on or dis tribu t io n
tr a n sformers . This stu dy, taking Arba Minch University main c a mpu s d i s t r i b uti o n sys t em
as a c a se s t ud y . tri e s to a ssess th e lo ad in g co n d it i ons of th e i ns t a ll ed trans for mer s in th e
selec t ed area by ta k in g actual l oad dat a, and i nves t i gate the re su ltin g t e c h nical and
e c onomic o u tco mes o f oper a tion at t hose conditions . Te c h ni ca l and ec onom i c a n a lys e s
were co n duct e d to s how the fi nanc ial and energy sav ings b e n e f i t s of acc ur a tely sizing
d i s tributi o n transformers. Re s ult s s h owed that selecting tran sfo r mer ra ting more cl osely
t o th e s iz e or th e l oa d may r esult in significant energy a n d cap it a l sa vi n g s . Fi n a l l y . l oad
es ti mati o n calcu l a ti o n s were carried ou t for sonic sections or th e d i st ribut i o n s ys t em to
s how how th e expe cted lo a ds on di s tributio n t ransformers differ from ac tu a l lo a ding s .
