Abstract:In order to solve the problems of photovoltaic on-site consumption and grid over-investment, a joint multi-stage dynamic planning method of energy storage system configuration and line capacity enhancement in active distribution network is proposed to cope with the increasing demand of load. From an economic standpoint, the photovoltaic consumption effect and peak shaving allowance obtained by joint planning are taken into account, and the planning objective function is suggested. At the same time, considering the installation area limits of distributed photovoltaic, a distributed photovoltaic development model is provided based on the Logistic curve, and then the installed capacity and output of photovoltaic in every planning stage can be predicted, which provides boundary conditions for the joint planning of energy storage systems and line capacity enhancement. Finally, phase angle relaxation and second-order cone relaxation are adopted to achieve convex optimization of power flow constraints and big-M approach is employed to obtain convexification of energy storage system constraints, resulting in efficient model solution. Comparing the system operating indicators of the before and after joint planning in a real distribution area, it can be seen that the system reliability after planning has a great improvement, and with the continuous access of distributed photovoltaics, the photovoltaic absorption rate does not decrease but rises, which verifies the effectiveness and practicality of the proposed joint planning method.