Study On Power Factor Issues Of Passenger Dedicated Lines

To meet the demand for railway transport market in China, the railway construction is developed faster and faster. The construction of passenger Dedicated line, not only achieve separation of passenger and freight, but also improve transport efficiency. With the opening of PDL, the adoption of new technology and new equipment, the traction power supply system demands to be safer. A series of voltage fluctuation, harmonic, negative sequence and power factor etc power quality issues are becoming increasingly showed in front of people.Power factor is not only a direct response to the active power and reactive power distribution in power supply system, but also one of the technical indicators of the quality of power supply. So the assessment of power factor has been emphasized by power system. Therefore improving power factor in technical and economic aspect are of great significance.Collecting data from Hefei-Wuhan Passenger Dedicated Line power supply system, especially the north Macheng traction substation section. According to the site record within oscillogram of the of voltage and current, the AT power supply system characteristics and the actual construction plan, it observed on the waveform and harmonic analysis, then reached a conclusion that the substation has a power factor problem. So adding compensation device was proposed.To north macheng traction substation as the prototype, the traction nets of unit length impedance and capacitance parameters were obtained by the equivalent reduction method of power transmission line with multi-conductor, and then established the traction nets parameter model. It built the simulation model of traction power supply system by MATLAB/SIMULINK in this paper. Simulation analysis of single train in traction condition, single train in braking condition, double train in traction condition, one train in traction condition the other in braking condition four cases. And of the actual situation, analysis of several reactive power compensations, TCR+FC Static Var Compensator device was selected. Finally it compared the simulation result with inputting the compensation device to compensation before, in technical and economic aspect, the harmonic reduced and the power factor reached the requirement. With actual characteristics of traction substation main connection, there is imbalance in the system. The electrified railway lines have a number of traction substations, when the commutating access of high voltage side of each substation in the power system, the negative sequence current significantly reduced. And because of its reduced operating costs, the compensation scheme is reasonable and feasible.Finally, the three-phase compensating device was joined in simulation model experiment, and the results show that the method can effectively eliminate the negative sequence current, balance three-phase system.