高压直流换流站换流阀开关电磁瞬态特性实验研究

Experimental Research on Switching Electro-magnetic Transient Characteristics of Converter Valves in HVDC Converter Stations

高压直流换流站中,换流阀开关电磁瞬态是稳态电磁骚扰分析和换流器均压设计的关键考虑因素。因此基于高压换流阀运行实验系统搭建了换流阀开关瞬态特性测量系统,获得了换流阀开通和关断过程中电压、电流瞬态波形,分析了电压、电流和磁场的频率特性,研究了换流阀工作电压、工作电流和结温对开通和关断过程的影响。结果表明,开通过程中电压呈指数变化,开通时间约为数μs;随着工作电压、工作电流和结温的升高,开通时电压下降时间随之上升,变化幅度可达20%以上;关断时间受运行电压、电流、结温的影响不明显,电流增大时,关断过程电压峰值也增大。因此,换流阀瞬态特性分析时,需考虑运行参数对开通和关断过程的影响。

Electromagnetic transient of valves in HVDC converters during turn-on and turn-off processes is the major factor for steady state electromagnetic disturbance（EMD） which is considered in analysis and grading devices design.Consequently,a measuring system for electromagnetic transient research was established.Transient waveforms of voltage across valve,current through it and magnetic field near it were gained during the valve operation.The spectra of voltage,current and magnetic field were analyzed.Influences of operating voltage,current and junction temperature on switching transients were studied.Results show that voltage changes exponentially during turn-on process,and the turn-on time is about several micro seconds.Turn-on time rises with increasing of operating voltage,current and junction temperature,the change amplitudes are up to 20%.Influences of operating voltage and junction temperature on turn-off time are not obvious.Therefore,the influences of operating parameters on turn-on and turn-off should be considered.