The increase of renewable energy sources (RESs)

especially wind power and photovoltaic

is bringing different fault features to the power system compared with the traditional synchronous generator

resulting in the urgent need for precise fault analysis. According to the sequentially activated fault features

the short circuit characteristics of RES can be divided into three fault stages. Within the staged framework of fault duration

the published research is reviewed to provide a systematic analysis of RES fault characteristics. It's concluded that the hardware parameter determines the sub-transient fault features of RES

whereas RES control begins to dominate during the following transient stage. However

the neglection of voltage transition and unavailable RES output phase shall impede the application of the analytical conclusions in protection design. To solve the existing problems

interaction among RES and networks must be figured out. Therefore

the fault calculation of the integral RES-grid system is offered as the research prospect.