In view of the insufficient economy and flexibility of AC/DC hybrid distribution network with high-permeability renewable energy access

we propose a daily-level optimized operation method of AC/DC distribution network with hybrid energy storage system

which is matched with the voltage regulation strategy of step-down transformer and voltage source converter. First

the HESS access capacity and location are determined on the basis of partitioning the distribution network by active/reactive-voltage comprehensive sensitivity. Secondly

based on the Hilbert-Huang transformation principle

the power distribution of the HESS composed of lithium batteries and supercapacitors is allocated. Then

a daily-level economic operation optimization model of AC-DC mixed-current distribution network is established in which the operating costs of the HESS’s full life cycle and the cost of main power purchase are taken into account. Finally

the typical second-order cone programming problem is solved. Improved IEEE33-node AC/DC hybrid distribution network simulation experiments show that HESS has obvious advantages in suppressing system high-frequency power signals and economy. On the basis of reasonable site selection and capacity

HESS combined with SDT and VSC voltage control can effectively reduce the voltage deviation that occurs during HESS operation

reduce the influence of voltage constraints on the HESS charging and discharging process

and further enhance the economic operation capacity and voltage stability of the distribution network containing energy storage.