| Over the last years, the use of non-linear power electronic loads, have increased the amount of harmonics in power distribution systems. The electric railway load is typical nonlinear harmonic sources, the opening of Zhe-Gan electric railway have a certain impact on Jiangxi power system. Therefore, it is necessary to analyze on harmonics of Zhen-Gan electric railway, and make relevant suppression strategy.Firstly, this paper introduces the basic concept of harmonic and the working principle of main circuit for electric locomotive typed SS4. According to the locomotive's running patterns and the change-over procedure of rectifier circuit, the harmonic analysis of locomotive is got by simulation.Secondly, Zhe-Gan electrified railway traction power supply system is analyzed, and the harmonic monitoring of traction substation is conducted. Then the harmonic filtering rate and the best option of harmonic suppression of electrified railway are got.Thirdly, this thesis outlines basic theory of APF, analyzes third currents detecting methods used in single-phase APF, and discusses the methods based on Instantaneous Reactive Power Theory, Active Current Separate Method and Unit Power Factor in detail. In comparison to third methods with MATLAB simulation, the third method is selected. This paper presents a topology of single-phase shunt hybrid active power filter (HAPF) and its principle. Then, the harmonic voltage and fundamental voltage control strategy of HAPF are analyzed. The voltage of active power filter can be controlled by system harmonic current, load harmonic current ,harmonic current of spur track, load harmonic voltage, or combination of them. Further more, a comparison research on different control strategies is put forward, the control strategy of ideal filtering is got ,and the system control strategy is determined at last.Lastly, PPF and APF of HAPF are designed, and the capacity of HAPF and APF is compared. PPF, APF and HAPF are simulated with the simulation of Yu-Shan traction substation. And it is validated that the designed HAPF can compensate harmonics and reactive of Zhe-Gan electrified railway effectively. |
