Static Voltage Security Region-Based Coordinated Voltage Control in Smart Distribution Grids

The high penetration levels of distributed generators (DGs), on the one hand, make the operational state of distribution grids increasingly complex; on the other hand, they enrich voltage regulation measures. Consequently, a voltage control strategy of the distribution grid for coordinating DGs and other voltage regulation devices is needed. This paper applies the security region methodology to coordinated voltage control. To meet the demand of online voltage security assessment and control in the distribution grids, a hyperplane expression for the boundary of the static voltage security region (SVSR) in complex power injection spaces is derived, and a corresponding fast generation method is proposed. Additionally, based on SVSR, a two-stage voltage control strategy is proposed. In the first stage, the regulation devices are automatically selected according to the coefficients in the hyperplane expressions, and the regulation effect can be estimated by SVSR. In the second stage, the outputs of the devices are determined by utilizing an optimization technique. The proposed voltage control strategy is tested by using a modified PG&E69-bus distribution grid, and the results verify the effectiveness.