Traction Substation Power Quality Assessment

At present,the rate of railway electrification in China has reached more than 60%.The rapid development of electrified railways has played an important role in promoting social progress and economic development.According to the "Thirteenth Five-Year Development Plan for Railways," the total mileage of China’s railway operations in 2020 will reach 150,000 kilometers.The electrification rate of railways has become an important indicator of the modernization of a country.In recent years,electrified railways have developed rapidly in the world.However,with the rapid development of electrified railways,the power of electric locomotives is increasing day by day,and the impact on the power grid is also becoming more and more serious.The large number of harmonics and negative sequence currents generated by electric locomotives are injected into the traction power supply system,resulting in a reduction in the power quality of the power supply system.Countries around the world have begun to pay attention to this issue and have taken various measures in accordance with the actual conditions of their electrified railways.This article first(bus)in shaanxi grid nodes can be divided into "traction,transformer hv side node"(hereinafter referred to as "traction defection point")and the common connection point "" two kinds,the power system harmonic current and fundamental negative sequence current calculation method of the algorithm and a variety of alternative power supply scheme of 110 kv voltage class calculation of harmonic and negative sequence to reveal MengHua railway harmonic and negative sequence in the distribution and characteristic of shaanxi power grid,and the calculated results are compared in detail and analysis,selected from a variety of solutions of shaanxi power grid power quality affect the smallest scheme,provide the reference for the planning and design departments.The paper mainly simulates and models electric locomotives,railway traction substations and power quality control devices,etc.,evaluates the power quality of traction substations,adopts reasonable control devices to manage power quality problems,and verifies the effectiveness of control.Comprehensively consider four typical operation modes at the planning level,various schemes for the traction substation access system,and the recent,long-term and average traction power,and maximum power,etc.,and calculate and evaluate the traction load access of the Mongolian railway to the Shaanxi power grid.The influence of harmonics,negative sequence and voltage fluctuations in quality provides reference for the planning and design department of the power grid.This kind of research on power quality problems,scientific and close to the actual engineering,has a strong theoretical value for solving the power quality problems of electrified railways,and provides a scientific theoretical basis for the application of post-engineering.