With the continuous development of new energy power generation technology, the access capacity of distributed photovoltaics continues to increase, and its impact on the power quality of the distribution network is gradually increasing. The access of distributed power sources brings many problems to the system planning, power quality, and relay protection of the power grid. From the perspective of power quality, this paper analyses the power quality problems caused by the grid-connected distributed power sources and the commonly used improvement methods, and expounds the role of microgrid technology in the hybrid access of multiple distributed power sources to the grid. At the same time, it expounds the technical hotspots of harmonic research on distributed new energy access to the power grid from the aspects of harmonic measurement, harmonic source location and responsibility assessment, harmonic resonance and its instability, and puts forward the future large-scale distributed new. The new harmonic research trend after energy integration provides a theoretical reference for the study of harmonic problems in the distributed new energy grid.