Evaluation Method of Static Voltage Stability of Renewable Energy Farm Based on Sufficient Conditions of Power Flow Insolvability

Due to the current limit and other factors, the voltage support capacity of new energy is weak, the static voltage stability risk of the station is high, and the existing analysis results are lack of intuition. In this paper, a static voltage stability analysis method of renewable energy farm based on the sufficient conditions of power flow solution is proposed to judge the existence and voltage stability of the power flow solution of renewable energy farm by solving the minimum voltage amplitude of the equilibrium node of the power grid outside the renewable energy farm. Firstly, by analyzing the static voltage stability problem of single-machine infinite system, the influence of the external voltage amplitude of the voltage source converter (VSC) on the maximum transmission power is analyzed using the analytical solution of the minimum voltage of the balance node. Secondly, for the static voltage stability problem of the radial multi-machine system, the DistFlow power flow model and its convex relaxation form are used to calculate the lower limit of the external power grid balance node voltage amplitude to determine the static voltage stability margin. The proposed method can provide the minimum equivalent voltage amplitude of the external power grid to maintain the stability of the static voltage of the renewable energy farm. In actual operation, the static voltage stability of the system can be efficiently evaluated by comparing the equivalent voltage of the external power grid with the calculated minimum equivalent voltage.