In this paper, the status quo, analysis methods and treatment technologies of steady-state power quality problems with the greatest impact and the widest impact on regional power grids are reviewed. The typical harmonic sources and their harmonic characteristics in the regional power grid are analyzed. The influence of harmonics on the regional power grid is briefly described. The main harmonic control measures are introduced in two categories: active and passive. The source, current situation and harm of three-phase unbalance in regional power grid are analyzed. The relevant standards and calculation methods of unbalance degree are emphatically introduced. The operation measures and treatment equipment to solve the three-phase unbalance problem are introduced. The current situation, mechanism and harm of low voltage problem in regional power grid are analyzed. The existing problems of low voltage monitoring are analyzed and the corresponding treatment technologies are summarized. Finally, the key to control the steady-state power quality of regional power grid is pointed out.