An improved voltage sag ride-through scheme for fuel cell based power quality control center

A novel voltage sag ride-through scheme for fuel cell (FC) distributed generator (DG) based power quality control center (PQCC) is proposed in this paper. Compared with the previous PQCC operational scenario, a series compensator (SC) which shares a same dc-link with the FC DG is integrated with the PQCC. Due to the fast and flexible power flow regulation capability of the PQCC-SC system, the sensitive load voltage can be restored to the pre-sag level if the upstream source undergoes a voltage sag. The interconnection between the upstream source and the PQCC can be reinforced significantly. A general relationship between the voltage sag magnitude, phase angle jump and the SC rating as well as the compensation constraints are established through power flow and phasor diagram analyses. The SC rating can be calculated based on the derived most onerous sag condition. Simulation results verify the efficacy of the proposed scheme.