Accuracy of current transformer with current errors at harmonics equal to the limiting values defined in IEC 60044-8 standard for transformation of distorted primary current

Accuracy requirements at harmonics are defined for electronic current transformers in IEC 60044-8 standard. As indicated there defined limiting values of current error ensure that the contribution of harmonics measurement error would add roughly 15%, in the worst case, on the theoretical error of the corresponding power metering class accuracy. In accordance with IEC 61000-3-12 standard total harmonic distortion of current caused by emission of higher harmonics from equipment connected to public low-voltage systems may be equal to 47%. Accuracy of 0.1-1 classes measuring current transformers with current errors at harmonics equal to the limiting values defined in IEC 60044-8 standard for transformation of such a distorted primary current may decrease over 12 times in relation to accuracy designated for transformation of sinusoidal current of frequency 50 Hz for which they were designed.