Transmission characteristics of harmonics and negative sequence components of electrified railway in power system

摘要

As a kind of large-power, single-phase and nonlinear load, the electrified railway produces a great deal of harmonic, which has a severe impact on the power quality in power system. In this paper, a set of practical indicators is put forward firstly, in order to analyze the transmission characteristics of the harmonics and negative sequence voltage and current in power network quantitatively. Secondly, based on a test data in a real electrified railway station and its electric supply station, the distribution and transmission situation of harmonics and negative sequence component of electric traction loads is analyzed. The transmission characteristics of the third, the fifth and the seventh harmonics, which are the main harmonic component of electrified railway load, are specially studied in this paper. Finally, an electromagnetism transient model of a power grid containing typical electric locomotives and tractive power supply system is established using PSCAD/EMTDC. The transmission characteristic of negative sequence component between two voltage grades was researched by simulation. The results show that the transmission characteristics of the simulation data are consistent with that of the test data, thus proving the correctness of the model. The influence of negative sequence component of electric traction loads to adjacent load substations are studied in the established model as a case study.