电磁式电压互感器谐波误差测量方法研究

为实现电磁式电压互感器在基波叠加谐波的实际波形下的计量误差测试,提出一种基于有源电子分压器的测量电磁式电压互感器谐波计量特性测量方法。以有源电容式分压器作为宽频比例标准装置,采用误差反馈技术,提高互感器二次转换单元测量准确度,基于LabVIEW和高精度数字化仪完成信号的测量和误差的计算,完成对4台电磁式电压互感器进行谐波计量特性测试。测试结果表明:随着谐波次数升高,在互感器的自身电感与分布电容的谐振处,误差急剧变化;二次负荷功率因数为0.8时,会对电压互感器的误差起到一定补偿作用,被试10 kV互感器在50-1500 Hz范围内,35 kV电压互感器在50-1000 Hz范围内,可满足电能质量监测要求。但从电能计量的角度出发,两者在50-2500 Hz范围内测量误差可满足要求。

Research on test method of harmonic measurement error of inductive voltage transformer

In order to test the harmonic measurement performance of inductive voltage transformers(VT)under the actual voltage waveform,a method based active capacitive divider was proposed.The divider was used as ratio standard,a feedback technology was developed to improve the measurement accuracy of converter unit for secondary voltage of VT,LabVIEW and the high-precision digitizer are used to measure the signal and calculate the errors.Four different types VT were tested based on this method,test results indicate that as the frequency of the harmonic voltage increases,VT measurement errors would change sharply due to the resonance of inherent inductors and stray capacitors.When the secondary burden power factor is 0.8,it would compensate the error of VT.And the measurement errors of 10 kV VT tested from 50 Hz to 1500 Hz,35 kV VT tested from 50 Hz to 1000 Hz would meet the requirement of power quality measurement.Moreover,according to the requirements of the harmonic energy measurement of VT in standards,the harmonic measurement errors of the VT under test were qualified in the range of 50-2500 Hz.