High-penetration distributed generations(DGs)connected into the distribution network leads to fluctuation and uncertainty in distribution network. In order to improve the capability of uncertainty treatment of distribution network

the flexibility enhancement of distribution network with high-penetration DG is studied. Firstly

the flexibility demand of distribution network with high DG penetration is explored. Then

five distribution network flexibility evaluation indexes are proposed

which include line capacity margin

transformer capacity margin upward

transformer capacity margin downward

net load fluctuation rate and maximum allowable net load fluctuation rate. The indexes represent the flexibility adequacy of distribution network capacity and the flexibility adaption of the embedded distributed generations

respectively. A multi-objective optimal scheduling model is established to improve the flexibility considering interruptible loads and energy storage. Simulation results show that the flexibility of the distribution network with high-penetration DGs can be improved by optimizing the scheduling of the flexible resources

and the hosting capability of distribution network for DG accommodation can increase.