基于同步压缩广义S变换的电力系统次/超同步振荡检测

Detection of Sub/Supersynchronous Oscillation in Power System Using Synchrosqueezing Generalized S-transform

为实现电力系统次/超同步振荡的快速、准确辨识,提出了一种基于同步压缩广义S变换(synchrosqueezing generalized S transform, SSGST)和改进稀疏时域法(improved sparse time domain method,ISTD)结合的次/超同步振荡辨识方法。该方法首先利用能量比函数对电力系统广域量测信息实时检测,当检测到信号能量发生突变时,利用SSGST对检测到的振荡信号分解得到相应的SSGST时频系数矩阵;然后通过改进的脊线提取方法在时频域实现对各振荡分量的最优轨迹搜索;进一步,结合最优轨迹时频索引重构各振荡分量的时域分量,并利用ISTD辨识方法计算出各振荡分量的频率和阻尼比系数;最后,通过自合成模拟信号、双馈风电场经串补并网系统仿真信号和某实际风电场实测数据验证了所提方法的准确性和有效性。

To realize the rapid and accurate identification of sub/supersynchronous oscillation in power system,this paper proposes a sub/supersynchronous oscillation identification method based on synchrosqueezing generalized S transform(SSGST)and improved sparse time domain method(ISTD).The method uses the energy ratio function to detect the wide-area measurement information of the power system in real-time.When the signal energy is detected to be abrupt,the SSGST decomposes the detected oscillation signal to obtain the corresponding SSGST time-frequency coefficient matrix.Then,the improved ridge extraction method realizes the optimal trajectory search of each oscillation component in the time-frequency domain.Furthermore,the time-domain components of each oscillation component are reconstructed by combining the optimal trajectory time-frequency index,and the frequency and damping ratio coefficients of each oscillation component are calculated using the ISTD method.The self-synthesized signal,the simulation signal of the doubly-fed wind farm through the series compensation grid-connected system,and the measured data of an actual wind farm verify the accuracy and effectiveness of the proposed method.