中文摘要：

提出一种基于S变换的时频分析方法，对信号的局部特性进行时域和频域的二维联合表示，S变换矩阵的行向量为信号某一频率处的幅值随时间变化的分布．列向量为信号某一采样时刻的幅值随频率变化的分布，即S变换的结果包含了频率一时间、幅值一时间和幅值一频率的信息，由此可以得到电压闪变信号的波动幅值、调制频率以及闪变发生的起止时刻。由于时频分析中时间分辨率和频率分辨率的不相容性．研究了S变换中高斯窗口的宽度对时频分辨率的影响，通过调节变换窗的参数实现了多分辨率的S变换．并给出了算法的实现步骤。仿真结果证明了所提方法的有效性。

英文摘要：

A time-frequency analysis method based on S-transform is proposed,which describes the local characteristics of flicker signal in both time and frequency domains. The row vector of S-transform matrix is the distribution of amplitude along with time at a certain frequency and its column vector is the distribution of amplitude along with frequency at a certain sampling time,i.e.,the results of S-transform contain the information of frequency-time,amplitude-time and amplitude-frequency,according to which,the fluctuation amplitude and modulation frequency of voltage flicker signal can be obtained,as well as its beginning and ending moments. Because the time resolution is incompatible with the frequency resolution in time-frequency analysis,the relationship between Gaussian window width in S-transform and the time- frequency resolution is studied. The multi-resolution S-transform is realized by adjusting the parameter of Gaussian window and the implementation steps are given. Simulative results show its effectiveness.