晶闸管换流阀反向恢复特性建模及阻容参数优化设计

晶闸管换流阀作为特高压直流输电的核心设备,其阻容参数设计关系到换流阀的性能乃至整个直流输电工程的安全可靠。基于晶闸管反向恢复电流的指数衰减模型,建立了换流阀关断时刻的数学模型,求解出晶闸管换流阀的反向恢复电压计算公式,总结出阻容参数对反向恢复电压过冲的影响规律。同时考虑关断时刻电压下降率、开通时刻电流上升率以及阻尼损耗等性能指标的限制,提出一种换流阀阻容参数的优化设计方法。在PSCAD/EMTDC中搭建12脉动换流器模型,对阻容参数的优化设计结果进行了仿真验证。

Modeling of reverse recovery characteristic and optimal design of resistance and capacitance parameters for thyristor converter valve

As the thyristor converter valve is the core equipment of UHVDC power transmission, the design of its resistance and capacitance parameters is related to its performance and even to the safety and reliability of whole UHVDC power transmission project. A mathematical model of converter valve at turning-off time is established based on the exponential decay model of thyristor reverse recovery current to solve the calculation formula for the reverse recovery voltage of thyristor converter valve. The influence of resistance and capacitance parameters on the reverse recovery voltage overshoot is summarized. A method for optimal designing the resistance and capacitance parameters of converter valve is proposed, which considers the limits of voltage drop rate at turning-off time, current rise rate at turning-on time, damping resistor loss, etc. A 12-pulse converter model is built with PSCAD/EMTDC for validating the results of parameter design.