High-Voltage, Direct Current (HVDC) Electric Power Transmission

Mercury Arc Valve

    Report from younger son that he has a job this weekend in Kristiansand, Norway, got me started on a Wiki wander. Kristiansand is at the Southern tip of Norway, closer to Denmark than Oslo or Bergen. So what kind of job has he got? Well, Wikipedia has this to say about the town:

Kristiansand has major shipbuilding and repair facilities that support Norway's North Sea oil industry. Near Kristiansand there is the static inverter plant of the HVDC Cross-Skagerak.

    The North Sea oil industry, eh? Well, that explains the job. But what's a static inverter plant and all the rest of it? An inverter converts DC electric power into AC. HVDC means High-Voltage, Direct Current. Cross-Skagerak is a high voltage electrical transmission line that connects Norway and Denmark.
    Being an American, I was brought up to believe that AC was the most efficient way to transmit electrical power over long distances, so I was a little non-plussed when I found out that there was a big HVDC line connecting Oregon to California. Now I find this in Wikipedia article #2:

The modern form of HVDC transmission uses technology developed extensively in the 1930s in Sweden (ASEA) and in Germany. Early commercial installations included one in the Soviet Union in 1951 between Moscow and Kashira, and a 100 kV, 20 MW system between Gotland and mainland Sweden in 1954. The longest HVDC link in the world is currently the Xiangjiaba–Shanghai 2,071 km (1,287 mi), ±800 kV, 6400 MW link connecting the Xiangjiaba Dam to Shanghai, in the People's Republic of China. In 2012, the longest HVDC link will be the Rio Madeira link in Brazil, which consists of two bipoles of ±600 kV, 3150 MW each, connecting Porto Velho in the state of Rondônia to the São Paulo area, where the length of the DC line is over 2,500 km (1,600 mi). (I've changed the links from useless to useful.) 

    The lines in China and Brazil were built by the Swedish company ABB. 

    I seem to be stumbling over a lot of Soviet and Chinese technology lately. Makes me wonder if America is really as great as we claim to be. I mean, why were we so intent on collecting all the Nazi rocket scientists after World War II? You'd think that if we were so great we could grow our own experts. We shouldn't need to import a bunch of Nazi's to do our thinking for us. I dunno, maybe it's expensive to grow experts. Maybe we saved a couple of bucks by stealing VonBraun and his gang. Still, something about that whole thing stinks.