电力系统保护与控制2023，Vol.51Issue(24)：33-43,11.DOI:10.19783/j.cnki.pspc.230511
基于半桥MMC特征信号注入的柔性直流线路频变参数辨识
Flexible DC line frequency-dependent parameter identification based on characteristic signal injection with HB-MMC
摘要
Abstract
The rapid rise of fault current in a flexible DC grid has a prominent contradiction with the weak overcurrent capability of power electronics elements.The DC line protection needs to complete the fault identification in a few milliseconds.Accurate parameter identification of transmission lines is very important in improving the performance of relay protection.However,the lack of a stable fundamental frequency in the DC system makes it difficult to obtain the relevant parameters of the transmission line and to realize the protection principle.There is difficulty in obtaining the frequency-dependent parameters of flexible DC lines.Thus a flexible DC line parameter identification method based on characteristic signal injection with a half-bridge modular multilevel converter(HB-MMC)is presented.By changing the control strategy of the converter,a characteristic signal is injected into the transmission line.Then the signal of different frequencies is extracted by fast Fourier transform and the line parameters at the specified frequencies are calculated.Finally,the corresponding amplitude-frequency characteristic curves are fitted according to the frequency-dependent characteristics of different line parameters.The simulation results show that the proposed parameter identification method can accurately fit the DC transmission line frequency-dependent parameters,and the relative error of the whole parameter identification is less than 1.5%.关键词
半桥模块化多电平换流器/特征信号注入/线路参数计算/频变参数Key words
half bridge modular multilevel converter(HB-MMC)/characteristic signal injection/transmission line parameter calculation/frequency-dependent parameter引用本文复制引用
聂铭,和敬涵,李猛,张慧媛,陈可傲,李艳..基于半桥MMC特征信号注入的柔性直流线路频变参数辨识[J].电力系统保护与控制,2023,51(24):33-43,11.基金项目
This work is supported by the National Natural Science Foundation of China(No.52007003). 国家自然科学基金项目资助(52007003) （No.52007003）
国家电网有限公司科技项目资助(5200-202256081A-1-1-ZN) （5200-202256081A-1-1-ZN）
