Which of the following factors determines the selection of voltage levels in primary and secondary transmission?

Voltage levels in the power system

• Primary transmission: Typically uses higher voltages (132 kV, 220 kV, 400 kV) to efficiently transport power over long distances. 
• Secondary transmission: Involves lower voltages (33 kV, 11 kV) to deliver power from substations to local distribution areas. 
• Distribution: The final stage uses even lower voltages (230 V or 440 V) for household and commercial use. 
   

Factors for selection of voltage levels:

The selection of voltage levels in primary and secondary transmission is primarily influenced by:

• Distance of transmission: Longer distances require higher voltages to reduce power loss (I²R losses) and improve efficiency.
• Power demand: Higher power demands typically require higher voltage levels to carry large amounts of power efficiently and safely.

The other options (type of power generation, transformers used, or number of consumers) may influence system design, but they are not the key deciding factors for transmission voltage levels.