基于线性补偿方式的电磁式CT负荷特性的研究

Research on error characteristic changing with burden for CT with linear compensation style

为分析二次负荷对电磁式电流互感器误差的影响,利用电流互感器的T型等效电路建立未经补偿电磁式电流互感器误差的数学模型,通过实验得出其负荷特性试验数据,进而拟合出负荷特性曲线。在分析各检定规程对电流互感器负荷箱计量性能要求的基础上,采用OMICRON公司的CT分析仪对两种不同相数和线圈外绝缘介质的电磁式电流互感器进行负荷特性试验。结果表明:高压电磁式电流互感器对二次负荷并不敏感,当负荷误差在-13%~13%变化时,比值差和相位差的变化还不到一个修约间隔;而对低压电磁式电流互感器而言,比值差最大变化超过1个修约间隔。

Mathematical model of uncompensated CT based on T equivalent circuits was established to analyze the CT error characteristic. Then the error characteristics changing with burden were obtained by experiment and simulation software MATLAB. Finally,the results were gotten by analyzing CT error characteristic with CT analyzer under the performance requirements of burden box of CT in calibration specification or verification regulation. The results show the error of high-voltage CT is not sensitive to the burden. When the load error in the range from-13%to 13% and the low-voltage CT,the ratio difference the biggest change more than 1 rounding interval.