This paper proposes a real-time voltage regulation for distributed power grids, which is able to determine a voltage control scheme including reactive power of wind power generators and conventional voltage controllers. Firstly, the statistics error distribution of wind power prediction in ultra short term is obtained. According to the active power of wind power generators and its prediction error, the available reactive power capability of wind power generators is determined. And then, a voltage control model with wind power generators, conventional generators, SVCs, switching capacitors and inductors is established. An improved interior point method is applied to solve the control problems. The proposed real-time voltage regulation is mainly achieved by the procedures involving determining the available reactive power capability of wind power generators, establishing the voltage control model, and solution using the improved interior point method. Finally, an actual distributed power grid is used to verify the effectiveness of the proposed control.