Simulation And Improvement Measures Research On The Electrified Railway Power Quality

Electrified railway has been developed rapidly in recent years, especially the high-speedtrain. It has become the main development direction. Electrified railway traction power supplynetwork is an important part of the electricity grid system. However, nonlinear and volatilityhave a great impact on the quality of electrified railway power load and harmonics, reactiveand negative sequence caused by the traction load are serious. It is more urgent to carry outcomprehensive management for quality of traction power supply system.Firstly, this paper introduces the existing models, describes its working principle in detailand builds a simulation model aimed at AD-CD-AD SS4electric locomotive. Then the powerquality characteristics of load current are obtained. Based on working principle andmathematic model of AD-CD CRH2EMU, the paper introduces the three-level four-quadrantconverter working principle and control strategy, builds a simulation model for CRH2EMU,provides basic data for comprehensive management.This paper introduces characteristics of passive filter and active power filter and explainscompensation effect of each device aimed at the mathematical model of the hybrid filter. Itcompares the working manner of passive filter and active power filter and introduces the wayto detect harmonic and reactive power current. The paper describes the control principle of thecontroller, builds a simulation model, verifies the effectiveness of controller usedin CRH2and compares the stability and robustness of the controller by changing theimpedance of the power supply system.At last, the paper builds a unified power quality conditioner based on controller byMat lab/Simulink. Proving the comprehensive compensation of conditioner is reasonable andefficient by comparing the simulation results.The focus and highlight of this paper are two parts. The first is drawing the conclusionthat the controller can adapt the impedance changing in power system based on AD-CDand AD-CD-AD locomotive and controller simulation model. The second is drawing theconclusion that the unified power quality conditioner based on H∞controller has greatdetection and control effect and provides theoretical basis for comprehensive development ofpower quality on traction power system.