Red Seal Powerline Technician Practice Exam

Which type of current is used for transmission in power lines?

1. DC (Direct Current)

2. AC (Alternating Current)

3. RF (Radio Frequency)

4. Pulsating Current

The correct answer is: AC (Alternating Current)

The use of alternating current (AC) for transmission in power lines is primarily due to its efficiency in transporting electricity over long distances. AC can be easily transformed to higher voltages using transformers, which allows power to be transmitted over great distances with reduced energy loss, as higher voltage transmission minimizes the heat generated by resistance in the conductors. This feature of AC makes it the preferred choice for utility companies, as it supports the infrastructure for a widespread power distribution system. In contrast, direct current (DC) is typically used for short-range applications, as it does not keep the voltage levels regulated over long distances as effectively as AC due to resistive losses. Radio frequency (RF) is not applicable for standard electrical power transmission but is instead used for wireless communication, and pulsating current refers to current that fluctuates in a non-constant manner, which is not suitable for consistent power supply and transmission.