Study On The Control & Application Of Power Quality About The Electrified Railway

Traction load in electrified railways is a kind of large-power, single-phrase and nonlinear load. Its random fluctuation character and abundant harmonic components make the electric networks full of negative-sequence current and higher harmonics, therefore, the energy quality is inevitably deteriorated. In the meantime, power factor of China's AC-DC electric locomotive is somewhat on the slow side, reactive component must be dynamically compensated in order to improve power factor of electrified railways.Based on the analysis of negative-sequence and harmonic components of electrified railways, a parallel capacitor compensation scheme is proposed. Two types of traction transformer in common use in Southwest Area are compared and the influence of traction transformer upon power quality is also analyzed in detail.Several dynamic reactive-load compensation equipments are introduced, such as TCR, TSC and SVG. The advantages and disadvantages of several combinations of APF and TSR are discussed. Furthermore, the test data of Yangmahe substation is examined carefully, leading to a typical evaluation of power quality.