Synthesis Design Of Novel Direct Current Transmission Analogue System's Filters

Harmonic suppression and reactive power compensation are the main problems in power system, this is very clear for direct current (DC) transmission system which adopts large power electric power converter technique. For the effect of high-capacity nonline load, the AC and DC side of the DC transmission exsist a large of harmonic and reactive power, it's necessary to carry out harmonic suppression and reactive power compensation.Based on the novel DC transmission and corresponding harmonic suppression's present and improvement, this paper put forward a novel inductive filtering method, which uses the transformer's amper-turn balance as the filtering mechanisim. This method realizes harmonic shielding according to transformer's zero impedence design and the tapping filters'full turned design.This paper detailed expoundes the novel converter transformer and corresponding inductive filtering technique's working mechnisim, transformer's impedence condition and its filters'turned condition. And it analyses the novel filtering method's technique characteristic and dominance, such as coupling action, reactive power compensation and harmonic shielding, etc. Based on this, this paper detailedly analyzes and calculates the novel DC transmission analogue system's harmonic characteristic, which considers the communation course, and obtains the detailed harmonic distribution condition, which is the precondition of filters'sysnthesis design.According to the design characteristics of the inductive filtering and passive filtering method, this paper compares the diffence filtering method's turned degree and design's difficult degree, then presents a drift-turned design method to the traditional passive filter's design. Also, the diffence filters'working mechanism and impendence-frequency characteristic are analyzed, and carry out the DC transmission system filters'sysnthesis design.Finally, this paper establishs the DC transmission analogue system's steady-state simulation model using Matlab/Simulink/PSB, and carries out detailed steady-state simulation and analysis. The we obtain the novel and traditional converter transformer's line-voltage and phase-current respectively, also contains their FFT results. The simulation results show that compared with the traditional passive filtering method, the novel inductive filtering method has a better effectness of harmonic shielding, and improves the valve line-voltage, which is good for converter's normal commutation and reliability. It can enhances the DC transmission system's stability.