This paper analyzes loop as the minimum unit

and presents an online adequacy evaluation model of power grid based on loop statistical reliability indices. The model collects loop statistical reliability indices online on the facilities of electric power reliability management system

and accesses the state of assess data online from the EMS. On the basis of traditional grid system reliability evaluation indices

three levels index of system-loops-node is established

fully reflecting the reliability of the electrical network. The actual assessment of power grid of certain a province in Central China indicates that the model is simple and effective

with the prospect of online applications.