Research On The Detection For Harmonic Accuracy Of Electric Instrument Transformer

With the wide application of power electronic technology, the harmonic pollution in power system is also growing worse,which becomes the focus of people's attention.It has make up the three public hazards in power system,with Low power factor and electromagnetic interference. Many scholars devoted to the study of harmonic harm, suppression and detection. On the other side, electronic transformer is widely used in electric power system. Compared with the traditional transformer,it has the advantages of wide frequency band, digital and so on.But the verification process of electronic transformer harmonic accuracy is not yet standardized and systematized. This paper designed a kind of class 0.2 electronic instrument transformer harmonic accuracy detection system.According to the national standard of electronic transformer, related technical indexes of this system are put forward. In the frequency range(49.5 Hz ~ 50.5 Hz),integrated accuracy the detection system should be at least class 0.05 so that it can test class 0.2 electronic instrument transformer. This System with high accuracy digital acquisition card as the core hardware,uses fast fourier improved algorithm for signal analysis. The main modules of the system are integrated in a portable industrial personal computer. This paper studies the asynchronous error in the process of acquisition card trigger. Also according to the theoretical study and simulation results, this paper analyzes the frequency shift error of traditional fast fourier algorithm.The detection system designs a fast fourier improved algorithm to correct the error.In the standard channel test, the integrated error of high accuracy acquisition card and software algorithm should be less than class 0.05 accuracy requirements,In order to ensure the traceability of the whole systemIn the basic accuracy test,this system is used to detecting the basic accuracy of a electronic instrument transformer with digital output. Comparing with eight and a half digital multimeter,the two groups of error results are similar,which both show that Calibrated transformer accuracy meet class 0.2 requirements.