基于Prony算法-准同步序列的超低频介损测量方法

超低频介质损耗因数测量方法，由于测量信号频率低导致采样时间长，采集数据量大，且在非同步采样时，快速傅里叶变换存在频谱泄露和栅栏效应，影响对介质损耗因数的精确测量。为降低测量信号采样时间和采集数据量，以及非同步采样时频谱泄露和栅栏效应，提出一种基于Prony算法 准同步序列的超低频介损测量方法，利用Prony算法并结合据辨识方法，对采样电压信号的基波频率进行预估，通过Newton插值算法，实现对电压和电流信号的准同步插值重构，获得采样信号的准同步序列，由FFT及介损等效电路模型，对准同步序列进行求解，实现对超低频介质损耗因数的求取。在频率波动、谐波含量变化、介损角变化和不同信噪比的噪声下测量介质损耗因数。仿真结果表明，该方法在软件上实现了准同步采样，有效降低了栅栏效应和频谱泄露对介质损耗因数测量的影响，并且采样时间短，采集数据量少，测量精度高，适用于对超低频介质损耗因数的精确测量。

Measurement of ultra-low frequency dielectric loss based on Prony algorithm and quasi synchronous sequence

For the ultra-low frequency dielectric loss factor measurement method, due to the low frequency of the measured signal, the sampling time is long and the amount of data collected is large. In addition, in the case of asynchronous sampling, the FFT has spectrum leakage and fence effect, which affects the accurate measurement of the dielectric loss factor. In order to reduce the sampling time and the amount of data collected, as well as the spectrum leakage and fence effect during asynchronous sampling, an ultra low frequency dielectric loss measurement method based on Prony algorithm quasi synchronous sequence is proposed. Prony algorithm and data identification method are used to estimate the fundamental frequency of the sampled voltage signal, and Newton interpolation algorithm is used to realize the quasi synchronous interpolation reconstruction of voltage and current signals, The quasi synchronous sequence of the sampled signal is obtained, and the quasi synchronous sequence is solved by FFT and dielectric loss equivalent circuit model to obtain the ultra low frequency dielectric loss factor. The dielectric loss factor is measured under the conditions of frequency fluctuation, harmonic content change, dielectric loss angle change and noise with different signal to noise ratio. The simulation results show that the method realizes quasi synchronous sampling in software, effectively reduces the influence of fence effect and spectrum leakage on dielectric loss factor measurement, and is suitable for accurate measurement of ultra low frequency dielectric loss factor due to short sampling time, small amount of collected data and high measurement accuracy.