IF we have 500kva transformer 11.0/0.415V, 50Hz. How to calculate the current o

IF we have 500kva transformer 11.0/0.415V, 50Hz. How to
calculate the current on HT & LT side, how can we consider
for its breaker (HT & LT both)? You are requested to solve
the question herewith.

Question Posted / sagir.bharat

Answers were Sorted based on User's Feedback

IF we have 500kva transformer 11.0/0.415V, 50Hz. How to calculate the current on HT & LT side, ..

Answer / antaratara ghosh

current on HV side= 500/(1.732*11)
= 26.24 A

current on LV side= 500/(1.732*0.415)
= 695.6 A

Breaker on HV side will be 630 A VCB (since it is the
lowest available VCB and in HV side you have to go for
VCB/SF6)

Breaker on LV side will be =greater than (1.2*695.6)A i.e.
834.72 A
so we consider it to be 1000 A ACB

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IF we have 500kva transformer 11.0/0.415V, 50Hz. How to calculate the current on HT & LT side, ..

Answer / sagir

Thanks for answer of this question.
Can you also clarify, on LV side you have multiplied the current with 1.2, why is this??

Also clarify we usually take 3Cx240 & 3Cx300 sqmm Al. cable from HV side. What is the calculation for this cable??

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IF we have 500kva transformer 11.0/0.415V, 50Hz. How to calculate the current on HT & LT side, ..

Answer / a.i.a

As, usually the ultimate load current for any distribution system take 20% spare loads for future , so full load current shall be multiplied by 0.2 more (i.e 1.2) to calculated MCCB rating.

hope you got the correct answer.

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