Research on a novel STATCOM based on hybrid cascaded multi-level converter and its coordination control strategy

A novel static synchronous compensator (STATCOM) based on hybrid cascaded multi-level converter (HCMC) is presented in this study, i.e HCMC-STATCOM, which combines the advantages of the traditional two-level converter and cascaded H-bridge converter. However, the topology and control system are relatively complex. It is difficult to coordinate the two key parts in steady operation. This study firstly introduces topology and working principle of the HCMC-STATCOM. Moreover then, the DC voltage of the two-level converter and the number of H-bridge sub-modules in WSC are optimised. In order to achieve the coordinated control of two key parts, a control strategy is proposed to achieve the coordination and synchronisation between the two parts of the HCMC-STATCOM. Finally the 35 kV/ ± 100 Mvar HCMC-STATCOM simulation model is built by using power systems computer aided design/electromagnetic transients including DC (PSCAD/EMTDC), the results show that the effectiveness of the coordinated control strategy and the accuracy of the theoretical analysis.