Abstract: After large-scale integration of high-penetration distributed photovoltaics into 10 kV distribution networks, bidirectional power flow will readily lead to a series of problems including node voltage violation, unbalanced reactive power distribution, increased line power loss and frequent switching of voltage regulation devices. Conventional centralized voltage regulation methods fail to accommodate the stochastic fluctuation of photovoltaic output. To address the above issues, this paper constructs a three-level collaborative voltage regulation framework covering substations, feeder partitions and station areas. Voltage-reactive power sensitivity and an improved K-means algorithm are adopted to realize adaptive reactive power partitioning of distribution networks. A multi-objective reactive power optimization model is established with the minimum network loss, minimum voltage deviation and minimum capacitor switching times as optimization objectives, and an improved PSO algorithm with linearly decreasing inertia weight is applied to solve the model. A simulation model based on the IEEE 33-node distribution network is established, and multi-working-condition verifications are carried out with the traditional voltage regulation scheme combined with standard PSO as the control group.