Which of the following is a common voltage for transmission infrastructure?

• A. Transmission Systems
• B. Distribution Systems
• C. Industrial Customer Systems
• D. Generation Systems

Answer: (A)

In power delivery, long-distance bulk transfer is most efficient when the voltage is very high, because that reduces the current and the I^2R losses in conductors. The part of the system that carries this high-voltage, long-distance power is the transmission system. That’s why it’s the best fit for a question about common transmission voltages. Distribution systems operate at lower voltages closer to customers, industrial customer systems stay within facilities at local voltages, and generation systems include the plant and its step-up to transmission voltage but are not the high-voltage network itself. Typical transmission voltages are in the tens to hundreds of kilovolts, while distribution voltages are much lower. So the transmission system is the network associated with the high-voltage transmission infrastructure.