Abstract:In order to ensure the safe and stable operation of the power grid,a high-frequency oscillation suppression technology of flexible DC transmission system based on sparse sampling and differential evolution is proposed to quickly restore the stable power supply capacity of the system.The MMC(Modular Multilevel Convert) high-frequency impedance model is constructed.The influence of link delay on the high-frequency impedance characteristics of AC system and the joint effect of transmission line parameter changes are analyzed and obtained.The sparse representation of high-frequency impedance signal is realized through A/I converter and matching tracking algorithm based on differential evolution,to reduce the sampling rate of high-frequency impedance signal of flexible DC transmission system,reasonably set the cut-off frequency,quality factor and compensation capacity parameters of additional RLC second-order high pass filter,adjust the impedance of flexible DC transmission system and suppress the high-frequency oscillation of flexible DC transmission system.The simulation results show that after the suppression of high-frequency oscillation,the voltage signal can quickly return to normal,and the suppression effect is prominent.