| Current transformers are not replaceable in the field of protection and measurement for decades, but the electromagnetic current transformers can not meet the development of the electric power system for the reasons of magnetic saturation, electromagnetic resonance, little dynamic range, narrow service band and so on. With the popularization of microcomputer, it will be irreversible to apply microcomputer in the protection and measurement, the equipments do not need the current transformer with high power, so the Rogowski coil can be applied on the field of protection and measurement. The digital signal analysis, research and process of the signal output from the Rogowski coil will be given in this paper.Firstly, on the basis of looking up the concerned technical literature and data both here and abroad, the paper introduces the fundamental principle and the operating characteristic of the current transformer based on the Rogowski coils, and gives the detailed description of the development and status now. After choosing the Rogowski coils as input part, the article gives the structure of the current transformer.Secondly, the project of the digital signal processing is discussed in the paper. By analyzing the principle of digital integrator, digital filter and temperature compensation, the article gives the design method about these digital arithmetic, how to choose the key parameter about the three arithmetic also has be introduced in paper.Finally, according as the regulation of the measurement error of the electronic current in the IEEC 60044-8, found the verify instrument of the electronic current transformer based on the technology of virtual instrument. The validity of this instrument is proved though the compare test. At last, the virtual instrument is used to test the output from the electronic current transformer, it takes the digital arithmetic introduced on the above, and the result proved the correctness of these digital arithmetic.
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