Autotransfomer standard sizes & ratio

[jhonwyn73]

There is an idea to have an Autotransformer of 500MVA 380/34.5kV. But we want to avoid the none standardized sizes/ratio(HV/LV).

Appreciate your help to know if such ratio (380/34.5kV) is widely used. Also, please help to know some references for the standard sizes & ratio, worldwide.

Thanks in advance.

 

[prc]

Never an auto-transformer is used for such voltage ratio.No advantage,in terms of cost and efficiency.Auto transformers are economical only up to a voltage ratio of 3.See earlier threads on auto-transformers 238-315162

 

[prc]

Also see Thread 238-300301. 500 MVA is a popular size.Nearest sizes in grids are 315 MVA and 630 MVA.Voltage ratios for auto-transformers are 380/220 or 380/110 or 132 KV.