A Back to Back HVdc Link With Multilevel Current Reinjection Converters

A back to back (BTB) HVdc interconnector consisting of multilevel current reinjection (MLCR) converters is described, based on the parallel converter configuration. Since the MLCR creates a zero current region during the commutations, the proposed BTB configuration permits the continued use of thyristor valves, without loosing the control flexibility of the self-commutating process. Extensive EMTDC simulation is used to demonstrate the satisfactory response of the proposed BTB HVdc interconnector control structure to varying active and reactive power operating conditions.