低气压直流转换开关开断能力研究

Research on the Breaking Ability of DC Conversion Switch Under Low Air Pressure

直流转换开关被广泛应用于特高压直流输电工程,用于系统运行方式的切换。其多采用无源自激振荡的技术路线,具有结构简单、性能可靠等优点。该文以直流转换开关为研究对象,通过SF6气体低气压特性分析,结合直流转换开关开断过程灭弧室的气流场仿真分析结果,优化气流通道,设计出适用于低气压环境的大容量开断装置。采用了低频振荡电流法等效直流电源进行直流转换开关的电流转换能力验证,分别在不同电流、不同气体压力时进行电流转换试验。由试验结果可知,随着开断装置充气压力的降低,电流转换的能力下降率达到10%~25%,且燃弧时间较长。通过仿真和试验研究,为低气压条件下直流转换开关的设计和电流转换能力评估奠定了基础。

Direct current(DC)transfer switch is widely used in high voltage direct current(HVDC)transmission projects,and used for switching the operation mode of HVDC transmission system.The technical route of passive self-excited os-cillation is mostly adopted,which has the advantages of simple structure and reliable performance.Therefore,the DC transfer switch is taken as the research object,then,through the analysis of SF6 gas low air pressure characteristics,and in combination with the simulation analysis results of the air flow field of the arc-extinguishing chamber during the switch-ing process of the DC transfer switch,the air flow channel is optimized,and a large-capacity switching device suitable for low air pressure environment is designed.The equivalent DC power supply of low-frequency oscillation current method is used to verify the current conversion ability of the DC conversion switch.The current conversion test is conducted at different currents and different gas pressures.The test results show that,with the reduction of the charging pressure of the breaking device,the current conversion ability decreases by 10%to 25%,and the arcing time is longer.Through simula-tion and experimental research,the result lays a foundation for the design of DC transfer switch and the evaluation of current conversion capability under low air pressure conditions.