230 kV is a common voltage for which portion of the electric power system?

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

Answer: (A)

High-voltage transmission lines are used to move large amounts of power over long distances with minimal losses. Elevating the voltage reduces the current for a given amount of power, which lowers I^2R losses and allows power to be sent efficiently across long distances and between regions. Generation output is stepped up to a transmission level, often in the range of 115 kV to 345 kV (230 kV being a common system voltage in many grids), and these high-voltage networks carry bulk power to substations near load centers. Distribution then steps the voltage down to distribution levels for local delivery to customers, and industrial customers typically receive medium-voltage feeds derived from distribution rather than 230 kV lines. Thus, 230 kV is best associated with the transmission portion of the electric power system.