A 350 kV HVDC Light® system stabilizes two weak networks in Namibia and enables power trading in the expansive region of southern Africa.
The Namibian transmission system operator, NamPower, chose the HVDC Light® system to electrically connect the northeastern part of the country to central Namibia, a distance of 950 km. ABB was contracted to build the 350 kV, 300 MW transmission link between Zambezi, close to the Zambian border in the region of Caprivi, and Gerus in the central part of the country. The two networks are very weak and the HVDC Light® technology helps to stabilizes them.
Gerus substation in the central part
of Namibia. Click for larger image | 
Zambezi substation in the Caprivi region.
Click for larger image. |
The HVDC Light® system is part of a greater scheme that includes a 950 km long DC overhead line, an upgrade of an existing AC overhead line from Gerus to Auas to 400 kV, the extension of the Gerus and Auas substations, and a new AC substation in Zambezi.
The Caprivi Link Interconnector, connecting electricity grids in Namibia and Zambia, ensures reliable power transfer capability between the east and west of the Southern African Power Pool (SAPP). It is also the first electrical connection between the Caprivi region of Namibia and the rest of the country, and is able to supply power to the region if normal supplies from Zambia are disrupted. Even larger islanded parts of the Namibian and Zambian grids can be supplied by the DC link, which maintains frequency control and thereby avoids power outages.
ABB was responsible for system engineering including design, supply and installation of the two converter stations and earth electrodes.
This project extends the voltage rating for HVDC Light® to 350 kV and marks the first time the technology is used for overhead transmission.
| Main data |  |
|---|
| Commissioning year: | 2010 |
| Power rating: | 300 MW |
| No. of poles: | 1 |
| AC voltage: | Gerus: 400 kV
Zambezi: 330 kV |
| DC voltage: | 350 kV |
| Length of overhead DC line: | 950 km |
| Main reason for choosing HVDC: | Long distance, weak networks |
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