An AC/DC Dedicated Collection Network-Based Grid Integration Method of Autonomous PV Inverters to County Distribution Networks

The construction of future power system with new energy as the mainstay is the core issue of the modernization of the national energy strategy of "carbon peaking and carbon neutral". The connection of high percentage of clean energy, represented by photovoltaic, to the county distribution network will bring disruptive changes to the traditional distribution network, and bring a series of serious challenges to the carrying capacity, grid-connected capacity and operation control capacity of the distribution network. In this paper, an AC/DC dedicated collection network-based grid integration method of autonomous PV inverters to county distribution networks is proposed for better grid adaptability. The proposed method is based on AC/DC collection technology and its performance is evaluated by a comparative study with the traditional PV grid-connected method. In the simulation experiments, under the same control conditions and topology, the THD of the proposed method is less than 2% which is greatly lower than the THD of the existing method, and the response speed and stability are faster. The study results show that the proposed method has better power quality, improved dynamic performance, and enhanced dc-bus voltage stability.