Fault distance estimation method for two-phase short circuit in distribution networks considering photovoltaic output characteristics

Abstract

The widespread integration of photovoltaic generation systems (PVGSs) has significantly altered the fault characteristics of distribution networks, thus impacting existing methods for estimating fault distances. Moreover, the current methods often suffer from complex principles, high costs, and limited universality, limiting their widespread application. In this study, the steady-state output characteristics of PVGS during fault ride-through periods are fully considered, and a composite sequence network for two-phase short-circuit faults in distribution networks with PVGS is established. The characteristics of two-phase short-circuit faults located upstream and downstream of the PVGS are analyzed. On the basis of this analysis, a novel fault distance estimation method for two-phase short-circuit faults based on the single-end steady-state current magnitude is proposed. This method only requires measurement of the fault phase current magnitude at the beginning of the line, thus offering low implementation difficulty and good cost-effectiveness. Finally, simulations validate the accuracy of this method under different fault locations and PVGS output levels and its robustness against measurement errors, various PVGS connection positions, and different loads.

Keywords

• Photovoltaic generation system
• Distribution network
• Fault distance estimation
• Two-phase short-circuit