After taking a look at the basics of electric power transmission and some facts of HVDC transmission, it is now time to learn some more facts about high voltage DC power supplies. Before that, just take a look at a typical system used to get DC power from an AC arrangement. The adjacent figure shows a simplified view of the overall power system from generation to transmission and final distribution. As you can see the various components of such a system are as follows.
Power House – this is the point where power is generated from various sources which could be say hydroelectric power, thermal power and so on. The given scenario shows two generators running in parallel and feeding the bus bars.
Bus Bars – there are two sets of bus bars in the diagram. The first one is located at the generation site and the second one at the sub-station site.
Transformers – there are several transformers which step up the voltage at the generation point and then for lowering this voltage at the sub-station.
The final delivery mechanism varies with the load requirements and shown in the diagram are three ways to convert this AC power to DC power. Each of these devices gives a different output which is used to supply electricity to different consumers such as domestic, industrial and so forth.
So you can see that in the above case the transmission is via AC supply but the distribution is by DC supply.