Based on the optimal ordering of network elements

the power outage range and isolation range are determined by the forward failure diffusion algorithm including several times of global network ergodic search. The nodes can be classified by enumerating fault elements without more global network search and accumulated to obtain the reliability indices

proving that the time complexity of the algorithm is O(N). According to the current changes through the load transfer path of corresponding outage element

the load transfer rates constrained by capacity and voltage are approximately calculated. Based on the maximum voltage drop of branches

the voltage constraint is conveniently checked. Thus

a simplified reliability evaluation model considering element capacity and node voltage constraints is proposed

with no need to invoke the full power flow calculation program. The validity and effectiveness of the proposed algorithm is verified through calculation and analysis of typical distribution networks.