Small-signal Stability Analysis of Three-phase Four-wire System Integrated with Single-phase PV Inverters Considering Phase to Phase Coupling Effect Under Asymmetric Grid

With the rapid growth of renewable sources energy, single-phase rooftop photovoltaic inverters (SIs) connected to distribution network have received widespread applications in recent years. In such a network, asymmetric fault problems are likely occur and small-signal stability during faults becomes an important issue. The existing papers analyzed sequence impedance related issues three-phase three-wire system. contrast, SIs four-wire systems requires consideration not only effect zero-sequence components but also phase coupling (PPCE). Because both component PPCE will affect characteristics inverter sub-system thus power Therefore, this paper established 3*3 admittance model matrix for considering frequency (FCE) under fault. Based on matrix, main factors including phase-locked loop (PLL) bandwidth grid neutral inductance that affects analyzed. addition, studies PLL bandwidth, short circuit degree location system stability. validity theoretical analysis is further verified through experimental results.