新型电力系统下电能质量信号的分数域降噪方法研究

“双碳”背景下,大量分布式电源接入电网引发电能质量扰动,给电网的稳定运行带来挑战。由于非线性、高速负载的大量集成,新型电力系统中的电能质量扰动呈现出非平稳特性,给降噪处理带来了新困难。针对这一问题,通过分析不同类型电能质量扰动在分数域的能量分布特性,提出了一种改进的基于分数阶傅里叶变换(FRFT)的降噪算法。同时,文章对分数阶最佳变换角度的估计方法进行了讨论,基于信号的分数阶频谱四阶原点矩,利用一维峰值搜索确定最佳变换角度可有效降低计算复杂度。实验结果表明,改进算法对平稳暂态扰动和非平稳暂态扰动均能有效实现降噪并保留暂态扰动的定位信息。

De-noising method based on fractional Fourier transform for power quality signals in the new power electronic power systems

Under the background of "dual carbon", a large number of distributed generation connected to the grid cause power quality disturbances, which pose challenges to the stable operation of the grid. With the integration of nonlinear and high-speed loads, power quality disturbance will exhibit non-stationary characteristics in the new power electronic power systems. By analyzing the energy distribution characteristics of different types of power quality disturbance in the fractional domain, an improved de-noising algorithm based on fractional Fourier transform (FRFT) is proposed. In addition, the estimation method of the optimal fractional transform angle is discussed. Based on the fourth order origin moment of fractional spectrum, the calculation complexity can be effectively reduced by using one-dimensional peak search to determine the best transform angle. The experimental results show that the improved algorithm can effectively reduce the noise of both stationary and non-stationary transient disturbances and retain the location information of transient disturbances.