Various faults will occur in the power grid during operation, among which the system short-circuit fault is the most common. The introduction of the photovoltaic system has changed the structure of the power grid. The power grid is no longer the original single-source radial structure, but becomes a dual-end or multi-end power grid, thus changing the size, direction, and duration of fault current. It is helpful to study the current output characteristics of photovoltaic systems in a short circuit for the study of the power grid. Therefore, this paper builds a grid-connected photovoltaic generator model on the DigSILENT simulation tool to study the output characteristics in a short circuit. The models are simulated under different conditions of three-phase short circuit, two-phase short circuit, and single-phase short circuit. Through analysis, it is concluded that the current characteristics of distributed generation with a power electronic interface are related to the design of the interface and the control method of an interface when a short circuit occurs.