In order to deal with the voltage control problem caused by the distributed photovoltaic(DPV)of high penetration level

the voltage control characteristics of the reactive power compensated PV and the voltage-controlled PV are analyzed. Considering the uncertainty of the output of load and DPV

an optimal reactive power dispatch(ORPD)model with long-time scale in distribution network considering the risk of voltage violation is proposed to minimize the operating cost. A probabilistic power flow calculation method in the distribution network is proposed

which contains PV nodes in order to solve the control problem caused by the voltage-controlled PV. The ORPD model aforementioned can be solved by the time decoupling and the catastrophic genetic algorithm. The simulation results show that the proposed method is able to effectively reduce the risk of voltage violation when compared with the existing DPV reactive power control methods. The ORPD scheme based on the voltage-controlled PV has a more significant effect on reducing the operation loss and suppressing the voltage fluctuation.