In spite of the difficult situation in central Africa, this HVDC transmission continues to deliver power.
The second to longest electric power transmission in the world, 1700 km, transmits power from the Inga falls in the Congo river to the copper mining district of Katanga in the Democratic Republic of Congo (DRC). The Inga-Kolwezi link was formerly known as the Inga-Shaba link.
| The Inga-Kolwezi is a ± 500 kV, 560 MW transmission. Because of the extreme line length and the difficult logistics along the route, it was decided to build two monopolar lines with four switching stations. The converter stations were built so that the two converter poles can be operated in parallel with ground return, in case of a monopolar line outage. |
The ABB contract for the converter stations was signed in 1973, but due to civil unrest in the country (then called Zaire), the transmission could not be taken into service until 1982. The link is owned by DRC's national electricity utility, Société Nationale d'Electricité (Snel).
Kolwezi station | 
Valve hall in Kolwezi |
Each valve hall in Inga-Kolwezi is equipped with six double-valves of air-cooled design. At the time, it was the highest valve voltage in the world, and each single valve has 258 series connected thyristors.
In 2009, ABB was awarded the upgrade of this link. The refurbishment, which includes delivery of new thyristor valves, high-voltage apparatus and the MACH2 control and protection system, will extend the life span of the link, enhance the reliability of the grid and ensure efficient transmission of hydro electricity across the region. It is scheduled for delivery in 2013.
| Main data |  |
|---|
| Commissioning year: | 1982
Upgrade: 2013 |
| Power rating: | 560 MW |
| No. of poles: | 2 |
| AC voltage: | 220 kV (both ends) |
| DC voltage: | ±500 kV |
| Length of overhead DC line: | 1 700 km |
| Main reason for choosing HVDC: | Long distance |
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