Under the deteriorated condition of environmental issue and resource crisis， the renewable energy with low emission and low pollution becomes the mainstream in the future. Photovoltaic（PV） system， as a kind of renewable energy， represents the future growing market segment. As the penetration level of photovoltaic system rises over the coming decades， reverse power flows on the distribution feeder will occur more frequently and the associated voltage rise might lead to violations of the permissible range of voltage. Various patterns of loads under different weathers and seasons are assumed and node voltages are analyzed by conducting a simulation with different photovoltaic system installation scenarios. The tap is changed to keep sending voltage and terminal node voltage within the permissible ranges continuously. A method is used to evaluate the influence of large-scale installation of photovoltaic generation on distribution networks from the view points of voltage profiles and reverse power flows. Finally， the electrical line losses of feeder with grid-connected photovoltaic system are given.