Influence Mechanism and Law of Source-Side Factors on Voltage Unbalance in Wind Power Gathering Network

As the penetration of new energy sources continues to increase, three-phase voltage unbalance frequently occurs in the centralized wind power integration systems in China, which threatens the stability and safety of wind turbines and power system. In order to analyze the influence mechanism and law of the source-side factors on the system voltage unbalance, this paper establishes the fundamental frequency negative sequence (FFNS) impedance models of doubly-fed induction generator (DFIG), wind farm and wind power cluster. A negative sequence equivalent circuit diagram, based on the actual network topology of wind power gathering system in North China, is derived, and the mechanism of voltage unbalance and the law of influence of source-side factors are analyzed. The mechanism and the impact law are verified based on