Short circuit analysis of PV inverter under unbalanced conditions with dynamic phasor sequence components

This paper presents a novel model for the short circuit analysis of PV inverter during transient period based on the dynamic phasor sequence component (DPSCs), especially the subtransient period (the first cycle after fault occurred). The model of photovoltaic (PV) inverter is presented as state space equations with DPSCs. The unbalanced fault condition can be given as the input vector in the state space equations. With supposing the states of the inverter controller keep constant during the subtransient period, then the state space equations can be solved and the fault current on ac side and the dynamic performance of the voltage on dc side can be calculated. With comparison of the simulation results, the model of PV inverter based on DSPCs can obtain the fault currents under different operation conditions. Above all, this is a new approach for the short circuit analysis for distributed generation in the distribution network.