Fixing Japan´s fragmented grid

The earthquake and tsunami that struck Japan in March blew a large hole in the country´s power supply. Japan´s grid managers are now hatching plans to beef up the country´s west-to-east power flow capabilities. As it stands, just three small installations, are able to squeeze power across Japan´s AC frequency frontier. These pull alternating current off one grid, convert the power to high-voltage direct current (H VDC), and then synthesize a novel AC wave to add the power to the other grid. Together these three facilities can push up to 1.2-GW of power east or west. The fastest way to add conversion capacity, is voltage-source converter (VSC) technology. VSC-based HVDC uses relatively advanced switches, such as insulated-gate bipolar transistors, to simultaneously transmit DC power and regulate the voltage of neighboring AC lines. VSC costs about 25 percent more than traditional HVDC, but it´s quicker to install.