WikiProject Power networks/HVDC-Scheme
An HVDC-scheme is a power transmission system where DC is used. As the required conversion from AC into DC and back into DC requires expensive equipment such transmissions schemes are only used when an AC transmission is not possible or inecconomic. Such cases are:
- Interconnections of power grids, which are not synchronized or used different frequencies and/or phase count
- Submarine cable transmissions over distances greater 30 km
- Overhead powerline transmissions over distances greater 400 km
For grid interconnections, there are also facilities, at which the conversion from AC to DC and back into AC on the same site. Such facilities are called HVDC back-to-back stations.
A complete list of HVDC schemes can be found on http://en.wikipedia.org/wiki/List_of_HVDC_projects . For most schemes oordinates of terminals are given.