基于短时傅里叶变换的电压暂降扰动检测

用短时傅里叶变换作为时频信号分析工具，研究在电压暂降扰动下暂降电压幅值检测、扰动时间定位和扰动源识别问题。提出利用暂降后电压信号的基频幅值曲线检测暂降电压幅值，利用暂降发生和结束时产生的高频信号对电压暂降扰动时间定位的方法，并提出根据基频幅值和扰动点个数来识别电压暂降扰动源的方法，该方法可以有效区分由短路故障引起的电压暂降和由感应电机启动引起的电压暂降。仿真试验结果表明该方法对电压暂降扰动检测精度高，同时比以往基于小波变换的方法在抵御谐波和噪声干扰方面更具有优越性。

Voltage Sag Disturbance Detection Based on Short Time Fourier Transform

Short time Fourier transform (STFT) was employed to measure the amplitude of voltage sag, detect interference instant and locate interference source. The amplitude of voltage sag was determined by the amplitude characteristics of fundamental frequency voltage and the high frequency signal produced when voltage sag starts and disappears was employed to identify the voltage sag inception and disappearance instant. A method based on the amplitude of fundamental frequency component and the number of signal singularities is proposed to locate interference source. The method can distinguish the voltage sag induced by fault from that induced by induction motor starting effectively. Simulation tests show that the method has high sensitivity and has better immunity to harmonics and noise than the methods based on wavelet transform.