Abstract: After a large-scale and high proportion of photovoltaic power generation is connected to the lowvoltage distribution network system，it will most likely cause the system power flow reversal，resulting in the out of limit voltage of each node of the system and the increase of system loss. First，using the line parameters and

topology of the low-voltage distribution network system，the sensitivity analysis of voltage-active power and

voltage-reactive power in the grid system was carried out，and the influence of distributed power access on the

node voltage of the distribution network system was derived. Based on this，a reactive power margin evaluation

method applying to low-voltage distribution network system with a high proportion of photovoltaic grids was

proposed. In order to reduce the amount of photo-voltaic active power reduction，an on-site active/reactive power

integrated control strategy was designed based on the network's reactive power sufficiency，and an adaptive

algorithm was used to optimize the control parameters between different nodes. The simulation results show that the proposed optimization control strategy can use the reactive power capacity of the inverter to adjust the system node voltage，effectively reduce the system network loss and photovoltaic active power reduction，and greatly eliminate the fluctuation of distributed renewable energy in the distribution network impact on system voltage.

      Key words: high-proportion photo-voltaic；photo-voltaic inverter；voltage limit；reactive power sufficiency；

adaptive algorithm