Abstract: To adapt to the transformation requirements of the power system, this paper researches the technical solutions and application value of Photovoltaic-Storage-DC-Flexible (PEDF) system in 110 kV substations. The overall design of the PEDF system is analyzed, and the functions of each component are clarified. A detailed analysis is conducted on the system's operating principles and control system architecture to achieve dynamic response, ensuring optimal and stable operation under various working conditions. Finally, by analyzing the practical application of a demonstration project, a comprehensive evaluation is performed on the economic efficiency, carbon emission environmental benefits, and the enhancement effect on grid reliability. The results indicate that 110 kV substations incorporating PEDF systems can improve the consumption capacity of renewable energy, yield significant economic and environmental benefits, and enhance grid flexibility and power supply reliability.