Abstract: For the problems that large computation, no real-time and low precision results using traditional threshold function detection when wavelet transform is applied to harmonic detection, a new online harmonic detection method is proposed in this paper, which applies lifting wavelet to signal sequence to deal with data processing of the new threshold function, while at the same time tracking harmonic current signals dynamically using sliding time window to achieve the online testing. To test harmonic detection capability of this method when non-linear load current is generated mutation, simulation model of the shunt active power filter is built up. Simulation result verifies that the online harmonic detection not only can separate the current component of fundamental wave and harmonic wave accurately, but also has better rapidity, real-time and accuracy.

Key words: Shunt Active Power Filter（SAPF）, online harmonic detection, lifting wavelet transform, sliding time window, threshold function

摘要： 针对小波变换运用于谐波检测时的计算量大、无法保证实时性、采用传统阈值函数检测结果精度较低等问题，提出了一种新的在线谐波检测方法，在运用提升小波对信号序列进行新阈值函数去噪处理的同时，采用滑动时间窗对谐波电流信号动态跟踪以实现在线检测。搭建并联型有源电力滤波器仿真模型，在非线性负载产生电流突变时测试该方法谐波检测能力，结果表明该方法能准确分离出基波和谐波电流成分，具有较好的快速性、实时性和准确性。

关键词: 并联型有源电力滤波器（SAPF）, 在线谐波检测, 提升小波变换, 滑动时间窗, 阈值函数