实时检测与定位电网电压瞬时波动的Coiflets小波方法

A Coiflets wavelet method for real-timely detecting and locating transient surges of network voltage

提出了一种基于Coiflets小波的实时检测与精准定位电网电压瞬时波动的分析技术。该方法除保留了一般小波分析所具有的局部时频多分辨分析能力和快速算法外,其顶层尺度分解系数就是电压信号的单点采样值,无需通常方法中所需的数值积分运算,有效减小了计算量,显著缩短了分析时间,增强了监控的实时性。通过定量研究4种典型的电网电压瞬时波动,结果表明所给出的Coiflets小波分析技术能够精准地识别出各种电压波动,其相对定位误差可达千分之一,明显优于现有方法;且其定位精度对电压波动的类型与幅值不敏感,保证了实际运用中分析结果的可信度。

A technique based on Coiflets wavelet analysis for real-timely detecting and locating transient surges of network voltage is proposed. Such a wavelet method holds both the ability in the local time-frequency multi-resolution analysis and the fast algorithm for general wavelet method. Most interesting, the top-level scale coefficient is exactly the single-point sampling value of voltage signal, with no need for numerical integration required in general wavelet method. This operation can effectively reduce the calculation amount, save the consuming time, and improve real-time performance. By quantitatively studying four typical kinds of transient surges of network voltage, the results demonstrate that the proposed wavelet method is capable of accurately identifying various transient surges of network voltage, and the relative error of location can reach one thousand which is obviously better than that of existing methods. More important, this accuracy of location is insensitive to the type and amplitude of voltage surge, leading to an excellent reliability of analysis result in the practical application.