Optimum design of low-voltage distributed photovoltaic systems oriented to enhanced fault ride through capability

The prescribed perspective of high accession of distributed generation photovoltaic (DG-PV) units on low-voltage distribution networks has brought up many issues regarding their performance in case of network transient phenomena. In this study, the design principles that DG-PV units must incorporate in order to meet the requirements of low-voltage ride through capability (LVRTC) are investigated through detailed theoretical analysis and calculations. The analysis shows that a realistic over-sizing of interfaced inverters of DG-PV as well as an appropriate selection of the equivalent interconnecting reactance X_DG, in conjunction with high penetration levels, can lead to satisfaction of LVRTC demands without violating the protection limits of the network. Moreover, the scenario of uniform dispersion along the distribution lines is proved rather favourable concerning the demand of LVRTC for voltage selectivity. Finally, considering the derived outcomes, a methodology of optimum design about LVRTC is proposed within the framework of reasonable constraints, which can be applied to any low-voltage distribution network.