Abstract: The volatility, weak feedback, and strong control of inverter interfaced distributed generation (IIDG) make it have different short-circuit current characteristics from synchronous generators under faults, and accurate analysis of them is the basis for the analysis of relay protection adaptability and the research of new protection principles, which is of great significance. Since the existing literature ignores the voltage amplitude detection delay and makes it difficult to accurately analyze the fault characteristics of IIDG, this paper takes the three-phase short circuit of the new energy transmission line as an example, comprehensively considers the influence of the voltage amplitude detection delay and the dynamic response characteristics of the phase-locked loop caused by phase jump, and finely divides the transient process of IIDG fault. It also establishes the fault current analysis expression under voltage and current loop control and current loop control for the two stages of the transient process of the fault. The influence mechanism of voltage detection delay and dynamic response of phase-locked loop on the transient characteristics of IIDG fault current is clarified. Finally, based on the Matlab/Simulink simulation platform, the correctness of the fault current analysis and calculation model proposed in this paper is verified.