High Voltage transmission started with the invention of the light bulb in 1879. The moment Edison invented the filament lamp it the transmission of energy became a necessary. From there the transmission of single phase started leading up to single phase transmission. With the evolution of the applications of electric power its transmission at longer distances started and the most feasible channel was the use of transmission lines. High voltage transmission could be done using alternating current (AC) or direct current (DC).
AC transmission Lines
In the case when electric power needs to be transmitted over long distances AC transmission involved the use of transformers which could either step-up the voltage level at the transmission end and step-down the voltage level at the receiving end. This approach does allow long distance transmission but it also increases the scope for power losses. The transmission lines that are used does not have any insulation on it due to which energy disperses in the form of ionization in the environment.
DC Transmission Lines
DC transmission line needs to be converted from AC to DC Converter station. All of the generated AC is converted into DC using the process of rectification and then moved from one place to another using transmission lines. From the transmission line, the DC to AC Converter station converts the DC back to AC and that’s how it gets transmitted from the generation grid to domestic usage.
Comparison between AC and DC transmission lines
In the case of high-voltage DC transmission, relatively the power losses are less as compared to AC transmission losses. DC Line losses are also less than AC Lines losses. Even when it comes to installing a DC transmission wire relevant to AC transmission wires, AC transmission installation and setup is more expensive than the DC transmission.