Study On Harmonic And Reactive Compensation Device Of Electrified Railway

Due to its own characteristics, the electrified railways with single-phase main frequency AC traction power supply system cause a lot of pollution to the electric utility system, which has serious impact on the quality of the power supply system and at the same time has significant effect on other users' power security and economic operation at the public access point. Therefore, the management of the harmonic and reactive power of the Electric Traction load has already become one of the significant subjects in the harmonic suppression and reactive power compensation areas.This paper first illustrated the systematic scheme and structure principle of the parallel hybrid power filter system (PHPFS), and then conducted a quantitative analysis of its reactive power compensation and harmonic theory. By theoretical derivation, PHPFS is proven to have the functions of compensating the harmonic and reactive power.One single-phase system reactive current detection method, a method that is based on the instantaneous reactive power theory of reactive current detection, is proposed on the basis of the existing current harmonic and reactive current detection methods, consequently, the speed and accuracy of the reactive detection can be improved. Meanwhile, deckle strap width control mode and PWM control mode based on the triangular-wave modulation are analyzed and researched in detail. According to the practical requirements, an improved triangular wave PWM modulation control mode is proposed, which makes it possible for the reactive power compensation device to work under the conditions of fixed-frequency and improves the current tracking accuracy.By analyzing the general requirements of the parameters design of the PHPFS, the relationship among the parallel active power filter (PAPF) parameters is found, and the design method of the main circuit of the active power filter is proposed. According to the literature available, design method of passive filter (PF) parameters is given.In light of he features of the electrified railway traction power supply system, a traction power System Simulation model with PHPFS is established in the PSCAD/EMTDC environment. Comprehensive research is conducted on the reactive power compensation and harmonic characteristics of the PHPFS, and the validity and feasibility of the system structure, control strategy and parameter calculation method is confirmed by the simulation experiment results obtained.