基于三次样条插值理论的电子式互感器数据同步

介绍了电子式互感器的数据同步问题,并对线性插值和二次插值的同步算法进行分析,指出线性插值算法在谐波次数高的情况下误差过大和二次插值算法在低采样频率下误差改进不明显。提出了基于三次样条插值理论的同步算法,并进行了误差的理论分析和数值仿真计算。理论误差分析表明,该算法相比较于线性插值算法和二次插值算法,误差值至少降低2个数量级;数字仿真验证显示,每周期48点采样时,稳态采样值最大误差约为输入电流最大幅值的0.000 38%,暂态采样值最大误差约为输入电流最大幅值的0.005%,采样值误差均降低2个数量级以上。在包含基频量和高次谐波电量的二次设备中,该算法可降低各采样点的相对误差,方法误差精度均可满足IEC60044标准规定的电子式互感器的误差要求,即稳态测量精度0.2级和暂态分量最大瞬时值误差小于±1%。

Data synchronization based on cubic spline interpolation for electronic instrument transformers

The synchronization of electronic instrument transformer data is introduced and the synchroni-zation algorithms based on linear interpolation and quadratic interpolation are analyzed,which shows that,the linear interpolation algorithm has large error when the order of harmonic is high and the quadratic interpolation algorithm has no obvious improvement when the sampling frequency is low.The synchronization algorithm based on cubic spline interpolation is presented with simulation and error analysis,which shows that its error is lower by at least two orders than that of linear interpolation algorithm or quadratic interpolation algorithm.Digital simulation shows that,the maximum steady-state sampling error is about 0.000 38 % and the transient sampling error is about 0.005 % of the maximum input current amplitude when the sampling frequency is 48 points per period.The proposed algorithm has lower relative error,suitable for measuring the harmonics and fundamental of secondary devices,and higher accuracy,meeting the requirements for electronic instrument transformer errors stipulated in IEC60044 standard,i.e.the steady-state accuracy class 0.2 and the maximum instantaneous transient component within ± 1 %.