Abstract: Unlike the traditional traction power supply system which enables the electrified railway traction substation to be connected to power grid in a way of phase rotation, a new generation traction power supply system without phase splits in power grid was proposed. Three key technologies of this system were discussed. First, the combined cophase traction power supply system was used for traction substation to realize negative sequence current control and eliminate phase split at the exit of substation. Second, new bilateral power supply technology was applied to eliminate the phase split at section post and reduce the influence of balance current on power grid. Meanwhile, power factor should be adjusted to ensure the voltage level of traction network. Third, the segment power supply and measurement control technology was used to divide the supply section into several segments and apply synchronous measurement technology to quickly and accurately diagnose fault and its location. Thus, the effects of faults can be limited to a minimum degree. Also, the economy and reliability of new generation traction power supply system were analyzed.