What is the cable sizing for a transformer 1.5 MVA 11kV/400V on the low voltage side?

Answer:

The cable sizing for a transformer depends on various factors such as the transformer’s power rating, voltage rating, and the length of the cable run. The cable size is determined by calculating the current that flows through the cable and selecting a cable that can handle that current without overheating.

For a 1.5 MVA transformer with a voltage rating of 11kV/400V, the current on the low voltage side can be calculated as follows:

  • Current on the low voltage side = (1.5 x 10^6) / (1.732 x 400) = 2175.5 A

To determine the appropriate cable size, you will need to consider factors such as the length of the cable run, ambient temperature, and installation conditions. You can refer to technical guides such as ABB’s ¹ for more information on designing and constructing transformer substations.

Please note that this is a general guideline and you should consult a qualified electrical engineer to determine the appropriate cable size for your specific application.