In order to do further research on co-phase power supply system, a test system based on YNvd balanced transformer, simulated load and integrated power flow controller (IPFC) is proposed. By mean of analysis on structures and principles of YNvd transformer, IPFC and simulation load, establishing control strategy on IPFC and simulation load, the system is simulated dynamically. The results illustrate that this scheme can well simulate the traction load and cycle the energy, simulate co-phase system, eliminate the system negative sequence, and compensate harmonic and reactive power real-timely, which verifies the feasibility of co-phase power supply system.