Abstract: With the increasing scale of new energy, flexible DC, FACTS and other new power electronic equipment connecting to the power grid, the operational characteristics of the new large-scale power grid have undergone significant changes, and electromagnetic transient refined simulation has become an important means of future power system simulation. However, the difficulty of electromagnetic transient modeling seriously restricts the widespread application of electromagnetic transient simulation. To address this challenge, a technical solution for quickly converting BPA data into ADPSS (advanced digital power system simulator) electromagnetic transient models was proposed, and corresponding software was developed. Through technical means such as modeling control by group, mapping modeling, user defined modeling, topology optimization layout, etc., the rapid automated conversion modeling from BPA data to ADPSS data was achieved. Finally, based on the BPA regional power grid data, a full electromagnetic transient modeling of a provincial power grid was completed using this software with the example scale exceeding 5000 three-phase nodes, and the modeling efficiency was greatly improved. The simulation results verified the effectiveness of the conversion modeling program.