采用全相位基波信息提取的介损测量

Using All-phase Extracting Fundamental Wave Information to Measure Dielectric Loss

为提高电容介损测量精度和降低计算量,提出了结合全相位数据预处理与基波信息提取的测量方法。并指出提高精度的根本途径在于改善序列截断引起的谱泄漏效应,故首先将电流和电压样本数据进行全相位预处理,然后将得到的数据与离散基波序列内积,再从内积结果提取电流和电压相位差而测出介损正切值。此方法无需引入附加的解析变换、数字滤波及离散傅立叶变换(DFT)措施,因而信号处理流程简单;由于全相位预处理抑制了各次谐波对基波的干扰,因而大大提高了测量精度。仿真实验表明:此算法的测量精度比传统正交滤波法高出2～3个数量级,其耗费的乘法计算量也仅为改进的正交滤波法的2.7%。

To improve the accuracy and to reduce the computation amount of measuring capacitor’s dielectric loss,we proposed a determination method combining all-phase data preprocessing and extracting the information of fundamental wave.It was found that the essential approach of enhancing the accuracy lay in improving the effect of spectral leakage arising from sequence truncation.Thus the current and voltage samples required to be all-phase preprocessed first,and the processed data and discrete sequence of fundamental wave were collected to make the inner product,from which the information of the phase difference between current and voltage could be extracted so that the tangent value of dielectric loss could be determined.The proposed method does not require any other measures like analytical transformation,digital filtering or DFT,the processing flow is simplified.Moreover,since the all-phase preprocessing can suppress the individual harmonics’ spectral interference on the fundamental wave,the accuracy is greatly enhanced.Simulation shows that the measuring precision of the proposed algorithm is 2～3 amount levels higher than that of conventional orthogonal filtering method.Moreover,the amount of consumed multiplication is only 2.7% of that of the modified orthogonal filtering method.