Fulin Zhou

Digital Detection, Control, and Distribution System for Co-Phase Traction Power Supply Application

Unbalance and reactive power currents of electric railway will result in poor power quality of three-phase industrial power grid. A co-phase traction power supply system is introduced in this paper to solve these problems by adopting single-phase ac-dc-ac converter. The converter is connected between two secondary windings of traction transformer with abilities of active power transmission and reactive power compensation. Because of the power conversion, the co-phase supply system can utilize single-phase feeding connection scheme instead of traditional two-phase feeding scheme. An actual 10 MVA/27.5 kV co-phase system with impedance-matching balance transformer is designed, developed, and tested. Its real-time detection, control, and distribution algorithms with field programmable gate array-based implementation are introduced. Some test running results validate the performance of the digital controller and demonstrate the feasibility of the proposed co-phase power supply system.

Co-phase power supply system for HSR

Poor power quality and phase splitting are the main issues in electric railway. Co-phase traction power supply system is adopted in electrified railway for active power balance, reactive power compensation and harmonic filter. The research development and application of co-phase traction power supply system in China are depicted detailed in this paper. Experiments and pilot project proved that good power quality, feasible, reliable and economical traction power system can be implemented in co-phase traction power supply system.

Co-Phased Traction Power System Based on Balanced Transformer and Hybrid Compensation

Power quality pollution to power system and locomotives discontinued current collection are caused by two phase traction power supply system in electrical railway. Cost-effective co-phased traction power systems (CTPS) consisted of balanced transformer, active power flow controller device (APFC) and passive compensation device (PCD) was presented to reduce power quality pollution and guarantee locomotives current collection continuously by canceling neutral section. Two schemes of CTPS were compared, parameter calculating method of PCD and control strategy of APFC are analyzed. CTPS and its control strategy have been verified based on MATLAB simulation.

Modeling and capacitance effect analysis of the cable traction network of an electrified railway

This paper models and analyzes the cable traction network (CTN) of a novel AC 110 kV-50 Hz cable traction power supply system (TPSS). First, we propose an equivalent model of the CTN that considers the charging current of the cables, in order to research the capacitance effect of the CTN. Then, three cases based on the novel TPSS are used to validate the proposed model, and to investigate the characteristics of the CTN. Simulation results show that the proposed model is effective in calculating both the charging current and the voltage on the cable system. Calculation results from case 2 show that the capacitance effect is mainly caused by the charging current flowing through the systems reactance, which consists of the reactance of the power system and the reactance of the main transformer. The reactance of the system, compensation coefficient and cable length can each influence the charging current and capacitance effect of the cable. Case 3 illustrates that the novel TPSS is very effective in supplying power and can greatly reduce the number of neutral sections; thus, it is suitable for application in future railway designs.