交-直-交电力机车接入的牵引供电系统电压波动特性

摘要

针对交-直-交电力机车接入牵引供电系统引发电压不稳、机车牵引封锁的现象,通过理论推导证明了该现象并非低频振荡而是电能质量问题.采用调制理论分析了低频调制信号在整流器中传播产生对称频率成分的机理;使用离散傅里叶变换分析了电压的不稳定特性,并采用总体最小二乘法-旋转不变技术的信号参数估计(TLS-ESPRIT)算法对其主导模态进行辨识,在此基础上将该现象定位为电压波动问题;利用不稳定电压的数学描述对信号重构,通过分析重构信号的多种性能评价指标进一步验证分析的合理性.%Aiming at the phenomenon of voltage instability and locomotive blockade in traction power supply system considering the AC-DC-AC electric locomotives accessed,it is proved that this phenomenon originates from a power quality problem in theory instead of a low frequency oscillation.The modulation theory is employed to analyze the mechanism of the symmetrical frequency component as a result of the low frequency signal transmitting in the rectifier.The voltage instability characteristics are analyzed by means of DFT(Discrete Fourier Transform),and the dominant modes are identified by the TLS-ESPRIT(Total Least Square-Estimation of Signal Parameters via Rotational Invariance Techniques) algorithm.On this basis,this phenomenon is defined as a voltage fluctuation problem.The signal is reconstructed by the mathematical expression of voltage fluctuation,and the effectiveness of the proposed methodology is further verified by analyzing the performance evaluation index of the reconstructed signal.