What is one characteristic of three-phase power systems?

Three-phase power systems are characterized by their ability to provide a constant power flow. This is due to the way the power is generated and distributed, with three alternating currents (or phases) that reach their peak values at different intervals. As a result, the power delivered to the load does not drop to zero, allowing for a smooth and consistent supply of electricity. This characteristic is particularly advantageous for industrial and commercial applications where a stable power supply is critical.

In contrast, single-phase systems experience power fluctuations, which can lead to less efficient operation in high-demand situations. The other options do not accurately represent the nature of three-phase systems. For instance, three-phase systems are not exclusive to residential applications; in fact, they are more commonly used in commercial and industrial settings. While they do indeed use less wire per unit of power transmitted compared to single-phase systems, that is not the primary defining feature. Additionally, three-phase systems typically operate at higher voltages than single-phase systems, making the use of lower voltage an incorrect description.