Smart VSC-HVDC Transmission

Smart Voltage Source Converter based High Voltage Direct Current (VSC-HVDC) is unlocking new possibilities for the grid of the future.

HVDC systems’ highly efficient transmission of bulk power across very long distances brings significant economic and technical advantages. However, deployment has traditionally been limited by problems surrounding power flow and protection when connecting to AC systems.

Introducing VSC power conversion addresses this challenge. VSCs can generate or absorb reactive power and allow real and reactive power to be controlled independently. What’s more, the direction of power flow may be reversed without changing the polarity of the DC voltage. VSCs do not depend on the presence of a synchronous AC voltage for their operation and may be used to feed weak or passive networks.

Technical details

Converters form the terminals of an HVDC transmission system and are used to adapt AC power to DC (rectifier) and DC power to AC (inverter). Conventional HVDC links are based on current source converters (CSCs) with thyristors; VSCs were first used in the late 1990s. 

Advantages of VSCs over CSCs are rooted in their use of self-commutated semiconductor devices such as insulated gate bipolar transistors (IGBTs). These can be turned on and off with a gate signal, bringing multiple advantages for power system applications. Benefits include independent control of active and reactive power at both converter stations as well as easy linkage of multiple terminals. Further advantages include the ability to supply power to weak grids and black-start capability.

VSC-HVDC demonstrator

RXPE has spearheaded Smart VSC-HVDC innovation and has numerous successful installations. We have a 36MW VSC-HVDC Demonstrator for long-term testing of our technologies; contact us if you’d like to visit this facility and witness VSC in operation.

Reference Projects

Technical parameters