Jiangxi ultra high voltage (UHV) accessed program is introduced. Based on uniform transfer equation, UHV π-type equivalent circuit is derived by considering the distributed parameter characteristics of UHV transmission line without conductance. Based on advanced digital power system simulator, the relationship of shunt reactor and steady-state voltage, as well as the relationship of shunt reactor and transient voltage, is achieved by using electromechanical and electromagnetic hybrid simulation, where the UHV between Hubei and Jiangxi is considered. Influences of shunt reactors’ location and the degree of compensation on UHV’s steady-state voltage and transient power frequency overvoltage are analyzed. The Logical results provide a meaningful guidance for the introduction of UHV power grid into Jiangxi power grid.