高压直流换流阀用集成式阻尼电容器设计与验证

Design and Verification of Integrated Damping Capacitor for High Voltage DC Converter Valve

阻尼电容作为晶闸管换流阀的重要组成元件,与阻尼电阻串联构成阻尼回路,并联于晶闸管两端,实现串联晶闸管的动态均压,抑制换相过冲,其参数及结构设计是换流阀设计的重要环节。针对换流阀小型化设计需求,提出一种集成式阻尼电容器设计方法。首先建立换流阀关断简化模型,采用解析法求解晶闸管最优阻容参数,并代入实际电路分析电容工作时的电气应力。然后,综合阻尼回路特点,提出扁平化集成式阻尼电容结构,并通过静电场仿真确定其壳体结构参数。最后,结合实际工程参数,从电气、结构两方面详细阐述扁平化集成式方形阻尼电容设计方法,并通过电容本体试验及在换流阀样机中的应用试验验证了所提方法的可行性。

The damping capacitor,as an important component of thyristor converter valve,is in series with damping resistor to form damping circuit,which is placed on both ends of thyristor in parallel connection so to achieve dynamic grading of series thyristor,suppress commutation overshoot.Its parameter and structure design are the important links in the design of converter valve.In view of the smart design requirement of thyristor valve,a kind of integrated damping capacitor design method is proposed.Firstly,a simplified model for switching off the converter valve is established,the optimal resistance-capacitance parameter of thyristor is solved by an analytical method and is substituted the real electric circuit to analyze electrical stress at capacitor operation.Then,the flat integrated damping capacitor structure is proposedbased on the characteristics of the damping circuitand its structural parameter of case is determined through simulation of electrostatic field.Finally,the flat and integrated square damping capacitor design method is described from such two aspects as electric al and structure with combination of actual engineering parameter.The feasibility of the proposed method is verified by the capacitor proper test and the application test in the converter valve prototype.