The voltage of point of common coupling(PCC)is susceptible to the random fluctuation of wind power when the grid at the connection point is weak. A hierarchical and coordinated control strategy for reactive power and voltage of wind farms is proposed based on the combination of multiple time scale vertical hierarchical thought and model predictive control(MPC)theory. Firstly

in the adaptive adjustment layer

an adaptive voltage regulation strategy is proposed according to the reactive power capability of the wind farm and the voltage prediction track at PCC. Secondly

in the reactive power distribution layer

the reactive power demand capacity is optimized

and an improved proportional allocation strategy that considers the reactive power margin of each generator is proposed. Finally

in the tracking control layer

the control error is corrected in real time according to the state prediction and reference as well as feedback information. Through hierarchical MPC

the prediction information of different time scales in each layer can be fully utilized

and the control between different layers can be coordinated effectively. The simulation results based on PSCAD verify the effectiveness of the proposed method. This work is supported by National Natural Science Foundation of China(No. 51607107)

Fundamental Research Funds of Shandong University(No. 2018JC029)and State Grid Corporation of China(No. 52060018000X).