Considering wide deployment of advanced IoT infrastructure in the future power system as well as the development of 5G technology, a fully distributed three-stage phase independently voltage regulation strategy is proposed in this paper. Voltage issue can be regulated collectively by utilizing the available real and reactive power of distributed energy resource (DER). In the first planning stage, a perturbation approach is proposed as the substitute of conventional Jacobian analysis to quantify the local voltage sensitivity in the three-phase unbalanced nonlinear distribution network under different R/X of the line. In the second stage, based on the consensus algorithm, an average voltage deviation can be achieved without the need of central controllers via an undirected communication network. In the third stage, independent droop controller of each DER is initiated to proportionally allocate the available P/Q of DER to support the voltage. Results of case study verify that the proposed regulation strategy can effectively deal with the unbalanced voltage problems in the network.