The power generation modes and grid connected strategies of DGs are diversified, and the transient and steady-state characteristics of the fault currents provided by DGs are much different from those of the fault currents provided by conventional synchronous generator. The special fault current characteristics of DGs make the conventional fault analysis method can be no more applied for the power grid with penetration of DGs. It is a new topic for the principle and setting calculation of the relay protection. According to the low voltage ride through (LVRT) control strategy of the corresponding DGs, the short-circuit calculation model of inverter interfaced distributed generator (IIDG) is established. Then, under serious and non-serious fault conditions, the short-circuit calculation models of doubly-fed induction generator (DFIG) are proposed based on the behavior characteristic of the crowbar. Based on this, a novel fault analysis method of power system with DGs is proposed. The simulation results show that the proposed method has a high accuracy of short-circuit current calculation and can meet the requirements of engineering application.