高精度介质损耗角实时在线测量方法

High precision real-time on-line measurement method of dielectric loss angle

为提高电气设备介质损耗角的测量精度,利用最优相关滤波法提取基波信号,通过短时傅里叶变换（STFT）插值谐波方法,抑制长频谱泄露的影响。仿真结果表明,最优相关滤波法可以克服加性噪声和调制性噪声的影响,在低信噪比情况下,能够有效消除噪声并检测出有用信号,提高STFT加窗谐波分析法的计算精度。系统频率在49.5～50.5 Hz时,该算法仍能保持较高的计算精度,且受频率变化影响较小。该方法能有效提高信号的分辨能力和准确度。

To improve the measuring accuracy of the electrical equipment dielectric loss angle, this paper introduces the use of optimization correlative filter to get the basal frequency signal and the use of the short time Fourier transform （STFT） interpolation harmonic method to restrain the influence of the long frequency chart leak. Emulation result indicates that the method can overcome the effect of additive noise and the modulation noise and, on the low signal-to-noise ratio, it can effectively eliminate the noise and detect the useful signal and increase measuring veracity of the STFT windowing harmonic method more. When the system frequency is between 49.5 and 50.5 Hz, the method can keep higher measuring veracity and suffer from less frequency change. The method affords an effective increase in the resolving power and the veracity of the signal .