Overview Voltage Sourced Converters (VSCs), applied to high voltage ac transmission systems, provides steady state and dynamic power flow control. They also offer steady state and dynamic ac voltage and reactive power control. Voltage Sourced Converters, as ac to dc and dc to ac converters, exhibit the unique capability for fast control of real and reactive power. These characteristics offer powerful means to improve performance of electric power systems, both at the transmission and the distribution level. The number of applications for voltage-sourced converters is presently small but growing. WG 15 received the mandate to review VSC applications in power transmission and to compare various topologies currently used. Special requirements for de capacitors, valve assemblies, cooling systems, reactors, magnetic interfaces, protective features and control modes of operation are also identified. The document addresses safety measures, design and production tests, equipment ratings, control and protection, installation, maintenance, field commissioning, testing and operation.