Management And Evaluation Of Electric Power Quality Of Electrified Railway Traction Load

In recent years,with the continuous enhancement of national economy,as the pillar of China's economy and the important national infrastructure,electrified railways occupies an important position in China's modern comprehensive transportation system.The stable and efficient traction power supply system is a necessary condition for the safe operation of high-speed railways.The traction load of electrified railway is a special asymmetric large capacity load with fluctuation,impact and nonlinearity.It will injecting negative sequence and harmonic current into the grid,which will seriously affect the power quality of the power system.Therefore,it is of great significance and practical value to carry out research and analysis on the characteristics of traction load of electrified railway and to manage and evaluate the power quality of electrified railway.The traction power supply system is analyzed in detail in this thesis,including the composition,the way of traction power supply mode,the type of electric locomotive,principle and types of traction transformer.It is systematically explained that the impact on the traction power supply system of electrified railway traction load and the harm to power system.Therefore,based on the AC-DC-AC HXD3 electric locomotive and combined with the power quality compensation scheme of China's current electric traction system,the working principle and control method of TCR+FC type single-phase SVC compensation are analyzed,and the control effect of power quality is verified by simulation.The compensation method of single-phase SVC parallel APF with better governance effect is proposed to improve the existing power quality compensation method.The simulation model is established by PSCAD software,and the treatment effect is verified.Meanwhile,three-phase SVG comprehensive compensation method is proposed for centralized governance of the electric traction system in the electrified railway dense area,and PSCAD is used for modeling and simulation verification of its governance effectBased on the industry standards and related standards in China and considering the current power quality detection level,the power quality evaluation index system of the traction load of electrified railway is established,and the weight problem is discussed in depth.In the evaluation index system,6 continuous power quality indicators of harmonic voltage distortion rate,frequency deviation,three-phase voltage unbalance degree,voltage deviation,voltage fluctuation and flicker and voltage deviation are adopted.Therefore,a comprehensive evaluation method for the power quality of railway traction load is established,which is based on the combination of subjective weight and objective weight.The weight of the method is determined by analytic hierarchy process and the entropy weight method,which takes into account the experience and judgment of the evaluator and includes the characteristics of the data.The results of comprehensive evaluation are more scientific and reasonable.