What transmission voltages are used?

What transmission voltages are used?

• A. 4 kV, 13 kV, 27 kV
• B. 69 kV, 138 kV, 345 kV
• C. 120/208 volts
• D. 208 volts

Answer: (B)

Transmission voltages are high-voltage levels used to move large amounts of power over long distances with minimal losses. The higher the voltage, the lower the current for the same power, which reduces I^2R losses in the lines. Common transmission voltages in many utilities include 69 kV, 138 kV, and 345 kV. These voltages allow efficient bulk power transfer between substations and big loads, with stages set up to step the voltage up for transmission and back down for distribution to customers. The other options are not used for transmission. Lower voltages like 4 kV, 13 kV, and 27 kV are typically distribution or sub-distribution levels closer to customers. Very low voltages such as 120/208 V or 208 V are service or end-user voltages used for actual building power, not for long-distance transmission.

Transmission voltages are high-voltage levels used to move large amounts of power over long distances with minimal losses. The higher the voltage, the lower the current for the same power, which reduces I^2R losses in the lines.

Common transmission voltages in many utilities include 69 kV, 138 kV, and 345 kV. These voltages allow efficient bulk power transfer between substations and big loads, with stages set up to step the voltage up for transmission and back down for distribution to customers.

The other options are not used for transmission. Lower voltages like 4 kV, 13 kV, and 27 kV are typically distribution or sub-distribution levels closer to customers. Very low voltages such as 120/208 V or 208 V are service or end-user voltages used for actual building power, not for long-distance transmission.