With theintegration of large-scale renewable energythe problem of the reduction of the regional voltage qualification rate becomes more significant than ever before because of the stability issues and the poor control performance of the renewable energies.In order to improve the accuracy and stability of the regional voltage, this paper investigates the reactive power limit of DFIGsby detailed calculation.The overcurrent factor is taken into account to further correct the reactive power lower limit of DFIGs.Thenthe control structure of DFIGs is improved by considering the reactive power capacity of GSCs in the DFIG reactive power compensation. Hence the reactive power compensation capability of the wind farm can be deeply exploited and the maximum active power would not be affected. In addition, a coordinated control strategy of wind farms and SVG is proposed, which can not only retain the flexible compensation capability of SVG, but also enable the wind farm to provide reactive power support and share the burden of SVG compensation.Finally, by analyzing parameters such as sensitivity and reactive power remaining, this paper designs a regional reactive power allocation strategy, which can further improve the voltage control performance. The control performance is verifiedthrough a two-area power systems with the integration of wind farms.