Dynamic performance of average-value models for multi-terminal VSC-HVDC systems

Voltage Source Converter (VSC) HVDC technologies present a bright opportunity in a variety of fields within the power system industry due to their recognized advantages in comparison to conventional line-commutated HVDC systems. Computational burden introduced by detailed modeling of VSC-HVDC systems in EMT-type programs complicates the study of transient events. Detailed modeling includes the representation of semiconductor switches and causes significant deterioration in computational speed. This paper presents the concept of average-value modeling applied to two- and three-level VSC-HVDC systems. The modeling approach is validated for a multi-terminal VSC-based HVDC system used to integrate off-shore wind generation. Dynamic performance simulation results using average-value models are compared against detailed model results. Some results are also presented for MMC converters.