With the increasing proportion of centralized and distributed new energy in the distribution network，the fluctuation and intermittency characteristics of these new energy cause more significant impact on the distribution network，which leads to frequent voltage fluctuations in the distribution network and brings unprecedented challenges to the reactive power support and voltage stability. In this paper，the voltage stability of the power grid operation due to the withdrawal of the reactive power compensation device of the new energy station is studied. The permitted maximum power generation output of the new energy station is studied from the aspects of theoretical compensation and system simulation when the static var generator of new energy station is removal from operation due to the maintenance or fault and also with consideration of the voltage variation of the gird connection point. The simulation results show that after the out of operation of the reactive power compensation device of the new energy station for some reason，the maximum active output of the photovoltaic power station is about 20% of the total installed capacity when the peak power load of the new energy station is required to give full play to the peak role. This conclusion can effectively guide the power dispatching agency to accurately control the power generation output of the new energy station so to improve operation efficiency and voltage stability of the power grid，and enhance the coordination and management ability of the dispatching agency to the power grid and the power supply.