As the development of social economy, the development
and utilization of new energy will be accelerated, VSC-HVDC
system will play an active role for new energy paralleling in
grid, so it will be paid more and more attention. As a new type
of power transmission and distribution technology,
VSC-HVDC technology still has many problems to take more
in-depth researched, discussed and solved, for example how to
improve the transmission capacity of VSC-HVDC to meet the
requirements of the long distance transmission.