| The new vehicles emerge in large numbers along with fast growing-development of thecity. The subway as an important part of the modern urban transport system caused morepeople’s attention to its safety and efficiency nowadays. The low-voltage distribution systemharmonic control problem of subway is becoming a new project. However, the designing,construction and operation of the subway and other related departments have no matureexperience. This project researches the harmonic control of the low-voltage distribution systemof subway-related, which analyzes and summarizes various harmonic source of subway,builds an accurate simulation model, studies the simulation results. To achieve the assessmentand calculation to the hazard of harmonic, the thesis compares and analyzes the calculation ofsimulation model and the measured data in order to provide governance scheme to harmonic,and also simulats various kinds of harmonic suppression schemes. After comparing differentschemes, the constructive governance scheme has been pointed out to be employed intolow-voltage distribution system harmonic control. It improves the security and reliability oflow-voltage distribution system, saves operating costs and results in direct economic benefits.The achievements of this thesis has profound guiding significance for the future subwaydesign, construction, operation.The major work and innovative content of this subject are as follows:1. This thesis deeply researches the subway various harmonic source of low voltagedistribution system, and analyzes the subway low-voltage distribution system harmonic datasystematically through the establishment of the mathematical models and simulation system.In the meantime, it analyzes the harmonic law and harmonic content which are caused bydifferent subway harmonic source. 2. It’s the first time that the electromagnetic transient simulation software PSCAD has beenemployed on the subway site to simulate mainly for the analysis of simulation model with thesoftware PSCAD to the lighting systems, environmental control systems, UPS, escalators andother types of harmonic source load simulations. It also analyzes the combined effects ofmulti-harmonic sources and calculated mathematical model superimposed.3.A full range of data of0.4kV low voltage distribution system harmonic source load onXi’an Metro Line2(Anyuan Gate Station, Bell Tower Station and Xiaozhai Station)has beencollected. Acquisition and simulation results and field data has been prepared during theresearch. The related calculated data can be used as the harmonic control equipment selectionand the basis for the development of harmonic control programs.4.The first time to use steady-state analysis method to study power system harmonic control.An innovative treatment of an“important load classification and concentrated compensationâ€has been pointed out that can be applied to subway low-voltage distribution system. It reducesthe interference that harmonics caused towards subway crucial equipment of communicationand signal. It also decreases harmonic impact on the power grid, and improves the safety andreliability of the subway low voltage distribution system.5.The first time to employ the power system steady state analysis method to studyenergy-saving governance effect towards the active power filter on subway low-voltagedistribution system. It compares the estimated energy saving effect which are brought bydifferent governance points.6. According to the harmonic treatment program designed by the results of this project, thestudy of simulation is carried out, which compares the power quality and waveform before andafter harmonic control device.7. It combines the measured results of harmonic suppression with the engineering operationcost to calculate the actual economic benefits. |
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