Motor Sizes

[pilts]

I have an apllication, where we I will be installing off 80kW pump motors. Initially it was assumed that these motors would be fed at 415 50Hz.
Can anyone suggest at what point it becomes economically viable to opt for H.V. (3.3kV or 6.6kV) drives as opposed to 415V.
The cabling itself is not really a problem as the route lengths are relatively short (i.e. <30M). However the feeding transformer will need to be in the order of 3MVA to cope with the other on site loads. This in itslef is a problem as 11/0.433kV 3MVA transformers are non-standard.

Thanks

 

[jbartos]

Please, see my posting in your other posting.

 

[cem]

It is economical to use MV motors for motors >160KW only.

 

[SooryaShrestha]

It seems you have other loads on 415 volt. Changing only for 80 kW load a 3 MVA transformer may be highly uneconomical, if there is no saving in other distribution loads. You need to make the overal study. Then only you will have fair picture of economy.
Make a spread sheet for all the decrease in losses using MV supply and the increase in losses due to further step down of the end use voltage. Take all the cost involved for different voltages. You will have one economic voltage. There are many many parameters to affect the economical cost.