In view of the power quality problems such as negative sequence and harmonics in V/v traction power supply system

we put forward a control strategy of a railway static power conditioner compensating for reference current rapidly and accurately. The operation principle of SS6 B electric locomotive is analyzed

and an equivalent simulation model which is suitable for power quality research is built. The generation mechanism of negative sequence and harmonic is revealed based on the V/v traction power supply system. The topology and compensation principle of the railway static power conditioner are analyzed

and the mathematical model for railway static power conditioner is established and the control equation of the compensation current is derived. Then the control strategy of railway static power conditioner based on improved sliding mode is proposed

which realizes the accurate tracking of the output current of static power conditioner and then improves the power quality of the V/v traction power supply system. The simulation model of SS6 B electric locomotive is proved to be correct

and the proposed strategy is proved to be effective by the simulations in PSCAD/EMTDC.