三端混合直流输电实验平台控制参考值变化斜率优化研究

Research on Optimization of Reference Slope for A Three-terminal Hybrid LCC-MMC HVDC Experimental Platform

摘要:

文中主要对结合电网换相换流和模块化多电平换流两种换流技术的优点的三端混合直流输电系统进行研究。由于调节9电平模块化多电平换流器（MMC）控制器的定功率值时，直流电压会出现一个瞬时增大或减小的值；调节25电平MMC控制器定电压值时，该支路交流电流会出现一个瞬时增大或减小的值；当调节控制器的值越快时，冲击量的峰值将会越大：因此通过爬坡实验，找到9电平MMC功率参考值Pref以及25电平MMC电压参考值Vref合适的斜率，使系统既有较快的响应速度，又不会因直流电压/交流电流的冲击过大而发生跳闸。分别通过仿真和实验验证，最终得到所搭建设备Pref的极限斜率为24 kW/s，Vref的极限斜率为1000 V/s，实验结果和仿真结果一致。

Abstract:

Combined with the advantages of line commutated converter and multiple module converter, LCCMMC threeterminal hybrid DC transmission system is mainly studied. When the constant power value of 9level MMC converter controller is adjusted, the DC voltage will increase or decrease instantaneously, and when the fixed voltage of 25level MMC converter controller is adjusted, the AC current of the branch will increase or decrease instantaneously. When the value of the controller [JP2]is adjusted faster, the peak value of the impact will be larger. Therefore, it is necessary to find the appropriate slope for 9level[JP] MMC power reference and 25level MMC voltage reference through climbing experiment, which will make the system not only have fast response speed, but also not trip due to excessive impact of DC voltage/AC current. Through simulation and experiments, the limit slope of power reference is 24 kW/s, and the limit slope of voltage reference is 1000 V/s, so the experimental results are consistent with the simulation results.