Please show all workSolutionThe single line diagram determin

Solution

The single line diagram determines the rating of equipment connected and is as follows:

1) Transformer rating: The entire load will be on the transformer and hence its rating approximately calculated as

10+12+10+(14.4+7.5+6)*0.9+20+40+7.5*0.746 = 122.7kW assuming a power factor of 0.9

Thus the transformer rating is 122.7*1.5 = 184.06kW which could be approximated as 200kW.

2) The circuit breakers rating will be approximately 50% above this rating to account for surges and all. Thus the rating could be 300kW.

3) The feeders could also of this size that is 300kW.