凯瑟窗改进谐波法测电力电容器介质损耗因数

针对基于快速傅里叶变换(FFT)的传统谐波分析法测电力电容器介质损耗因数(tanδ)时会由于非同步采样和非整周期截断造成频谱泄露和栏栅效应的问题,依据凯瑟(Kaiser)窗函数主瓣和旁瓣衰减比例自由选择的特性,采用基于凯瑟窗的相位校正的改进谐波算法测量电力电容器介质损耗因数.在电网基波频率变化、介损角真值发生变化以及白噪声干扰等3种条件下,仿真分析该算法和基于Hanning窗、Blackman窗的插值算法的测量误差,并通过实验进行验证.结果表明,该算法与Hanning窗和Blackman窗插值算法相比能更有效地克服基波频率波动及白噪声等对电力电容器tanδ测量的影响.基于Kaiser窗函数的改进谐波算法抑制频谱泄漏效果好,准确度高,满足电力电容器介质损耗因数tanδ在线监测的要求.

Modified Harmonic Analysis Method of Kaiser Window to Measure Dielectric Loss Factor of Power Capacitor

Aiming at the problem of spectrum leak and picket fence effect caused by the nonsynchronous sampling and non-integer-period truncation when the traditional harmonic analysis method based on FFT is used to measure dielectric loss factor（tanδ） of power capacitor,according to the Kaiser window function＇s characteristic that the attenuation proportion between main lobe and side lobe can be chosen freely,the modified harmonic analysis method based on Kaiser window phase correction is used to measure tanδ of power capacitor.In three conditions of grid frequency fluctuation,the true value of tanδ change,and the white noise interference,the measurement errors of this algorithm and the other interpolation algorithms based on Hanning and Blackman windows are simulated and analyzed,and the results are proved through experiments.The results show that the algorithm can more effectively overcome the influence of fundamental wave frequency fluctuation and white noise than the Hanning window and Blackman window interpolation algorithms on the electric power capacitor tanδ measurement.The effect of restraining frequency spectrum leakage of the modified harmonic analysis method based on Kaiser Window is good,the method has high precision,and can meet the requirements of tan δ online detection of power capacitor.