基于小波变换与希尔伯特-黄变换的微电网暂态电能质量扰动检测及辨识研究

由于可再生能源接入微电网会给其带来很多电能质量问题,因而对微电网的电能质量信号进行检测及辨识十分必要。但在对电能质量信号进行采集与检测的过程中极易受到噪声的干扰,有效地降低信号中的噪声且完整地保留下反映信号突变特征的奇异点是检测其电能质量扰动的基础。而传统检测方法基本只适用于稳态电能质量扰动且抗噪性较低。为提高在噪声条件下检测的准确性,本文提出了一种基于小波变换和希尔伯特-黄变换的微电网暂态电能质量扰动检测及辨识的方法。该方法使用小波阈值去噪方法消除信号噪声,并利用小波变换和希尔伯特-黄变换对微电网暂态电能质量扰动进行辨识及检测,同时进行了计算机仿真验证,仿真结果表明:该方法去噪效果明显、辨识效果显著、检测精度高、实用性强。

Study on Detection and Identification of Transient Power Quality Disturbances of Microgrid Based on Wavelet Transform and Hilbert-Huang Transform

Since the access of renewable energy to the microgrid will bring many power quality problems,it is therefore necessary to detect and identify the power quality signal of the microgrid.However,it is highly susceptible to noise interference during the process of collecting and detecting the power quality signal.Reducing effectively the noise in the signal and completely retaining the singular point reflecting the sudden change of the signal is the basis for detecting the power quality disturbance.The traditional detection method is basically only applicable to steady-state power quality disturbance with low noise immunity.In order to improve the detection accuracy under noise conditions,in this paper a method based on wavelet transform and Hilbert-Huang transform to detect and identify transient power quality disturbance in microgrid is proposed.The method uses wavelet threshold de-noising method to eliminate signal noise and uses wavelet transform and Hilbert-Huang transform to identify and detect the transient power quality disturbance of microgrid.At the same time,computer simulation is carried out.It is shown by the simulation result that the method has remarkable de-noise effect,significant identification effect,high detection precision and strong practicability.