Voltage stability analysis method of distributed photovoltaic integration based on improved V-Q sensitivity

Large-scale integration of distributed photovoltaics into power grid has a certain impact on the voltage stability. By assuming that the voltages of generator terminals are constant, an approximate model describing the voltage magnitudes of load terminals is derived and an improved V-Q sensitivity method is proposed. The difference between the proposed method and V-Q sensitivity based on power flow equation is compared, and the advantages are pointed out. In the simulation of 33-bus distribution system and 6268-bus East China Power Grid, the effectiveness of this method is validated, and the voltage stability of distributed photovoltaic integration is analyzed. The conclusions are as follows: The V-Q sensitivity matrix has the characteristics of being almost all positive, diagonal elements all positive, block diagonalization and weak diagonal dominance; distributed photovoltaic connected to weak voltage nodes can effectively raise the grid voltage and at the same time improve the static voltage stability.