Analysis of AC/DC Side Harmonic Interaction of Back-to-Back VSC Based SNOP

Soft normally open point (SNOP) is power electronic device installed in place of normally-open point (NOP) in electrical power distribution networks. The application of SNOP has the potential to improve the power supply reliability and power quality of distribution network. Background harmonics in the distribution network will cause abnormal fluctuations in voltage and current. Based on the working mechanism of SNOP, this paper analyzes the generation process of harmonics on the AC and DC side of SNOP. The correctness of the proposed analysis is demonstrated through simulation results.