Question { 45070 }

What are the different protection systems used to protect
the transformer internally and externally?

Answer

https://library.e.abb.com/public/4381d7d675f760cdc12575550081d599/AG03-5005E_en_Power_transformer_protection.pdf

Question { DAE, 1967 }

Fault current shall be part of tech specs of power cable or not?.

Answer

During a short circuit, a high amount of current can flow through a cable for a short time. This surge in current flow causes a temperature rise within the cable. High temperatures can trigger unwanted reactions in the cable insulation, sheath materials and other components, which can prematurely degrade the condition of the cable. As the cross-sectional area of the cable increases, it can dissipate higher fault currents for a given temperature rise. Therefore, cables should be sized to withstand the largest short circuit that it is expected to see.

http://www.openelectrical.org/wiki/index.php?title=Cable_Sizing_Calculation

Question { 1766 }

How to calculate voltage drop in copper and aluminium cable?

I have laid 240Sq.mm Aluminium cable for the length of 600 Mtrs in 1 Mtrs underground.
Normal load is 150A. Transformer is 630KVA, 6.KV/433V. But, I am getting only 395 Volts when load. How to calculate voltage drop and what is the permissible voltge drop for this circuit?

Answer

http://www.openelectrical.org/wiki/index.php?title=Cable_Sizing_Calculation