二次侧注入扰动的变流器次超同步频段广义阻抗测量方法

基于广义阻抗的稳定判据充分考虑了次超同步频段电网和变流器的耦合作用,并可将系统稳定性分析转化为对单输入单输出系统的分析。从二次侧注入扰动不仅可以测量变流器的广义阻抗,相比一次侧注入扰动,还具有成本低、操作简单的优势。为此,提出了二次侧注入扰动的变流器次超同步频段任意功率因数下广义阻抗测量方法。首先,推导了任意功率因数下的系统广义阻抗和考虑二次侧扰动信号注入的原-对偶复电路;然后,从电路的角度解释了所提广义阻抗测量原理;最后,根据测量原理给出了该频段二次侧注入扰动的变流器广义阻抗测量方法。所提方法是现有广义阻抗测量方法的推广,通过仿真分析可验证所提方法的有效性。

Measurement Method for Converter Generalized Impedance in Sub- and Super-synchronous Band Based on Perturbation on Secondary Side

The stability criterion based on generalized impedance fully considers the coupling effect between the grid and the converter in sub- and super-synchronous band, and can transform the analysis of system stability into that of single-input-single-output system. Injecting disturbances on the secondary side can not only measure the generalized impedance of the converter, but also have the advantages of lower cost and simpler operation compared with injecting disturbances on the primary side. To this end, a measurement method for generalized impedance of converter based on perburbation on the secondary side in sub- and super-synchronous band with an arbitrary power factor is proposed. Firstly, generalized impedance of the system and the primary-dual complex circuit considering the perturbation on the secondary side are derived. Secondly, the principle of measurement method for generalized impedance is explained from the point of view of circuit. Finally, based on the measurement principle,measurement method for the generalized impedance of converter perburbation on the secondary side in this frequency band is proposed. The proposed method is a generalization of existing measurement methods for generalized impedance. Simulation results verify the effectiveness of the proposed method.