1 Cable sizing for 630KVA Auxiliary Transformer
Rating of the equipment 630 kVA
Voltage 415 V
Full Load current 876.49 A
Cable type considered 1C x 630 sq.mm. AL, XLPE
Rated continuous current
when
565 A
directly laid in ground
Derating Factors
a) Variation of ground temperature 0.91
b) Variation of ground temperature 1.11
c) Group rating factor for 3 group of cables in
trefoil formation and touching each other
0.88
d) Rating factor for depth of laying 0.91
Composite derating factor (a×b×c×d) 0.81
Continuous current rating after applying the
derating factor
457.02 A
Hence number of run required 1C x 630 sq.mm. AL, XLPE
For the Phase 2 Nos
For the Neutral 1 Nos
Total run 7 Nos