Power Quality Characteristics Analysis and Research Progress of AC/DC Distribution Networks

With the increase of the penetration rate of new energy and the access of DC flexible loads such as charging piles, AC-DC interconnected power supply can effectively improve the reliability and stability of the distribution system, which is an inevitable development trend of the future distribution network. However, the grid-connection of high-permeability renewable energy generation devices and power electronics with a high proportion of broadband output characteristics has led to a continuous reduction in the inertia level and damping capacity of the distribution network, posing new challenges for power quality analysis and proactive governance of power systems: On the one hand, it changes the power quality form and transmission characteristics of the traditional AC distribution network, and on the other hand, it brings new means and ideas for the improvement of power quality. Therefore, starting from the voltage level, grid structure and control strategy of the new AC/DC distribution network, this paper deeply analyzes and summarizes the power quality characteristics under the new situation, and sorts out the existing power quality comprehensive assessment methods and optimization measures. Finally, the future direction of power quality index system, evaluation method and active governance strategy is prospected from the perspective of the characteristics of the new AC/DC distribution network, which provides reference for further theoretical research and engineering problem solving.