Against the background of the interconnected structures among substations in smart distribution network

this paper proposes a stochastic planning method for distribution network based on security distance to improve power supply efficiency and save investment cost. Firstly

the method and indices for N-1 security evaluation of the distribution network are described based on security region methodology. Secondly

the fault load restoration as well as uncertainties of time-varying load and distributed generator(DG)output is considered for the chance-constrained distribution network planning model

which aims to minimize the present value of total cost. Then

the hybrid solving strategy in conjunction with fuzzy C-means clustering and dynamic niche differential evolution algorithm is utilized to solve the model. Finally

compared with two available planning methods

planning results show that the scheme proposed can improve power supply efficiency of the original network and optimize system economy and security at the same time on the premise of N-1 security. The methodology is more suitable for short-term planning of urban developed distribution networks

which have the characteristics of slow load growth and scarce line corridors.