Virginia Smith Converter Station is a high-voltage direct current (HVDC) back-to-back station near Sidney, Nebraska at 41°09′51″N 102°59′15″W / 41.16417°N 102.98750°W named for former Congresswoman Virginia Smith, a Nebraska Republican who represented Nebraska's 3rd congressional district from 1975 to 1991. Virginia Smith Converter Station was built by Siemens and began service in 1988. The station can transfer a maximum power of 200 megawatts; the voltage used by the station is 55.5 kV.
Timing differences in continental-sized nations make national power grids based solely on conventional alternating current impossible. However, power can be transferred over longer distances and between separate AC grids by conversion to direct current during transmission, and conversion to alternating current in phase with the local line frequency at the delivery point. By the early 21st century, high-power semiconductors began to make the more difficult DC-to-AC conversion technically and economically possible at the high power levels needed in power grids. The Virginia Smith Converter station is significant for being the first interchange between eastern and western United States electrical grids.