In order to gain an understanding of the effects the photovoltaic(PV) generation might have upon the voltage stability in distribution grid,a general PV grid-connected power generation system(PVGS) circuit model based generalized load is built in this paper,and is applied to study the voltage stability.The simulation results show that voltage fluctuation is deeply affected by the fluctuation power,the power factor and the voltage levels of distribution grid.The basic approach to improve voltage stability is...