A highly accurate ECT calibration system based on virtual instrument technology

An electronic current transformer (ECT) calibration system based on virtual instrument technology is introduced in this paper. The system uses the fourth-order convolution window algorithm for error calculation method. Compared with Fast Fourier Transform, which is recommended by standard IEC-60044-8 (Electronic current transformers), it has higher accuracy. The relative measuring errors caused by asynchronous sampling could be reduced effectively without any special synchronous sampling technique adopted. The present system is realized by virtual instrument and the results show that the ratio error caused by asynchronous sampling can reduced to the order of 10^-4, and the phase error can be reduced to the order of 10^-3 degree, when the deviation of frequency is within plusmn0.5 Hz. The present method of measurement processing is achieved by vitual measurement devices, with low cost and short empoldering period.