Multipulse VSC based SSSC

The aim of this paper is to cover a comprehensive set of topics in order to contribute to the study of multipulse voltage sourced converter (VSC) based static synchronous series compensator (SSSC). The topics covered consist of full topology analysis as well as its voltages and currents, detailed modeling and laboratory implementation. The configuration studied is a 24-pulse VSC based SSSC. The detailed configuration of the VSC circuit along with its description is presented. Details about the internal functioning and topology connections are given in order to fully understand the construction of the VSC output voltage and its harmonic content, based on expressions derived. Also, equations that completely describe the VSC internal and dc currents are given. Using the voltage and current analysis of the topology, a 24-pulse switching functions (SF) model is presented. The model correctly represents commutations of semiconductor devices in a VSC, which consequently allows a precise representation of harmonic components. The model is carried out in the original abc power system coordinates. Effectiveness and precision of the model are validated against PSCAD/EMTDC simulations. Additionally, in order to accomplish a more realistic comparison, a laboratory prototype set up is implemented to assess simulated waveforms.