The distribution characteristics of new energy make it easy for near power failures to occur in new power systems, leading to it being difficult to ignore the impact of three-phase asymmetry on inverter power supply. The traditional positive sequence model for inverter power supply can only symmetrically output reactive power compensation. It cannot accurately calculate the near power asymmetric faults. First, this paper points out the problems of the existing low-voltage ride through specifications when three-phase asymmetry occurs. It improves them, and designs a set of asymmetric low-voltage ride through specifications using phase voltage indicators. Then, a universal fault calculation model for the inverter power supply is established, and its equivalent methods when connected to high current and low current grounding systems are analyzed respectively. The effectiveness of the model is verified through simulation of the single power supply system. Finally, the phase component fault calculation method for the new power system is proposed, and the substitution calculation methods for various fault types and inverter power supply model are derived. The correctness of the proposed algorithm is verified through numerical examples.