When is DC transmission typically used?

DC transmission is typically employed for large amounts of power over long distances due to its unique advantages in minimizing power losses and increasing efficiency in transferring electricity. When high voltage direct current (HVDC) systems are used, they can significantly reduce the resistive losses that occur during transmission compared to alternating current (AC) systems, especially over vast distances.

This is because, in a DC transmission system, the current does not reverse direction, which eliminates issues such as skin effect and reactive power losses that are prominent in AC systems. Additionally, DC transmission allows for the interconnection of asynchronous power systems, meaning different power grids that are not synchronized can be connected effectively.

Furthermore, the ease of controlling power flow and reduced footprint of HVDC lines (compared to their AC counterparts) make DC systems ideal for long-distance transmission, particularly in scenarios where renewable energy sources are situated far from population centers and demand areas. This capability to effectively deliver large amounts of power efficiently over long distances distinguishes DC transmission from other applications.