The intermittence of the renewable energy sources in active distribution network (ADN) has made a higher requirement for voltage control. At the same time

more controllable elements such as energy storage devices and distribution flexible AC transmission systems equipment have increased the complexity of voltage control

posing a greater challenge to the conventional voltage control strategy. A hierarchically coordinated voltage control strategy is proposed based on the complex controllable elements and flexible structure of ADN. The control framework is developed by referring to regional control and autonomous control as well as the radial structure of distribution network. The index of equivalent voltage level is also proposed to distinguish the control boundary

thus avoiding repetitive adjustment. On the basis of former indices

the strategy takes full advantage of voltage regulating equipment

such as on load tap changing transformer

capacitor

static var compensator and distribution energy resources to achieve voltage recovery. Finally

the robustness of the proposed control strategy is verified by simulation. This work is supported by National High Technology Research and Development Program of China (863 Program) (No. 2014AA051902).