Abstract: In this paper, the technical bottleneck of the static frequency conversion starting system (SFC) in pumped storage power plants introduced early in our country is studied, especially the design voltage is low, the working current is large, the water cooling heat dissipation requirements are updated to the application requirements of the air-cooled heat dissipation, and a large capacity SFC reconstruction scheme based on the air-cooled heat dissipation technology is proposed. The design, development and test of DC 4000A air-cooled pumped storage SFC power panel are analyzed in detail in this paper. Relying on the SFC system modification project of Tongbai pumped storage power plant in East China, the one key selection startup control flow is established and the on-site commissioning is completed. Field test data showed that the unit startup time was shortened to 198s after modification, and the temperature rise was controlled within ΔT≤40K, 20% more than the original system capacity. Engineering practice shows that this scheme successfully realizes the transformation of heat dissipation mode and performance leap of SFC equipment under the constraints of retaining the original transformer, and significantly improves the operation reliability of the equipment.