Ultra High Voltage – or UHV – is defined as voltages of 1 000 kV alternating current, or higher, and 800 kV direct current, or higher, and it is needed for two main reasons. The first is to deliver large quantities of power over very long distances with very little loss of power (higher voltage means lower current on the transmission line and therefore lower loss). The second is to deliver large quantities of power to cities without having a proliferation of transmission lines.

If you can deliver lots more power with just one line, you do not have to build more lines and the resulting overall impact is reduced. In places where demand is growing but room for transmission lines is limited this is critical because it means only one power line corridor is needed, not several. International standards for UHV do not exist yet, so they need to be developed to ensure the safe and efficient use of this technology. It is a technical challenge for manufacturers, utilities and, ultimately, a regulatory issue for governments. IEC and CIGRE are the bodies responsible for technical specifications for this technology.