基于S变换的电力系统间谐波检测

Detection of inter-harmonics in power system based on s-transform

电网中常存在许多频率与基波成非整数倍的间谐波。S变换是由连续小波变换和短时傅立叶变换结合发展起来的另一种时频分析方法,具有概念清晰、结果直观等优点。本文首先分析了应用S变换时频分析进行电力系统间谐波检测的基本原理,然后对平稳间谐波和电压波动引起的动态间谐波等典型算例进行了计算仿真。仿真结果表明,该方法能很好地检测平稳问谐波的幅度及频率,并能较好地检测动态变化间谐波,实现间谐波的有效分析。

There are some inter-harmonics in power system, which has not integer times of basic frequency. The S-transform was an extension of continuous wavelet transform and short-time Fourier transform. For its good time-frequency characteristic, it was suitable for inter—harmonics detection. In this paper, time—frequency analysis based on S-transform was used for detection of steady inter-harmonics, dynamic inter-harmonics from voltage fluctuation. The simulation results showed that the proposed method could not only get frequency and amplitude of steady inter-harmonics effectively, but also can detect dynamic inter-harmonics.