Market-oriented reform is the development trend of regional power grid integrated with high penetration of distributed energy resources (DERs). This paper investigates a market-oriented operation mode of regional power grid based on power quality management plan. The dynamic hierarchical organization structure of the market-oriented operation of a regional power grid is presented at first. The energy management system satisfying the steady-state power quality control of regional power grid is designed, the structures and interaction of the network energy management subsystem and source-load energy management subsystem are explained. Based on these works, the energy management process based on power quality management plan is developed, and the functional modules of each market member are designed based on cognitive agent template. This paper provides a reference for solving the steady-state power quality problems of a regional power grid under the market-oriented mechanism.