Utilizing Balanced and Unbalanced Partial Techniques in Co-Phase V/v Railway System for Improving Hybrid SVC Power Quality Conditioner

This paper proposes a hybrid structure including static VAR compensator (SVC) and conventional hybrid power quality conditioner (HPQC) in co-phase traction railway system powered by V/v transformer. The SVC plays a vital role in compensating the full required load reactive power in addition to filtering the third and fifth harmonics, while the HPQC handles the left harmonics and negative sequence current of the grid side. Moreover, to keep the grid power factor flexibly within acceptable limits, a control strategy employs two partial compensation techniques, one balanced and one unbalanced (BPCT and UPCT, respectively). The proposed arrangement not only drastically improves power quality indices (PQI) but also reduces HPQC capacity by as much as 23%. Since the hybrid structure has a lower capacity and higher performance than the conventional one, it may be a viable option for achieving power quality targets in electric rail networks.