In order to solve the power quality problems

such as harmonic

reactive power

and negative sequence in the three-phase line side of the electrified railway traction power supply system

and to meet the needs of heavy compensation capacity of the electrified railway

a comprehensive compensation scheme

which was formed by the railway static power condition（RPC） and the step-down transformer

was proposed

and the control method of the parallel RPC was specifically researched. The balanced compensation current detection method was used in instruction current detecting and triangle wave comparison of proportion resonance（PR） controller was used in compensation current controlling. Also

the carrier phase shift（CPS） technology was applied in RPC controlling. At last

the modeling and simulation of the compensation scheme which was composed of two parallel RPC were built on the MATLAB/Simulink. The simulation results show that the three-phase line side currents will keep balanceable after one fundamental frequency cycle when RPC has been put in operation. By adopting the CPS technology further

the three-phase line side currents total harmonic distortion rate is reduced from 8.04% to 2.24%. The research work here confirms the feasibility and superiority of the parallel RPC for solving the power quality problems in the three-phase line side of the traction power supply system

and also provides a valuable reference for the engineering application of the parallel RPC.