Intelligent Design of Low Voltage Side Circuit in Active Electronic Current Transformer (英语论文).doc

PAGE \* MERGEFORMAT 1 Intelligent Design of Low Voltage Side Circuit in Active Electronic Current Transformer ABSTRACT With the development of power industry and the increase of voltage level, many problems of electromagnetic current transformer had emerged, thus the concept of electronic current transformer was proposed by International Electro-technical Commission (IEC) in order to solve those questions. Thereinto, the active electronic current transformer is considered as the most feasible. However, many disadvantages such as high cost, low generality and intelligence were encountered when using Normal Integrated Circuit in the low-voltage side. A new designing method of low-voltage side circuit is introduced in this paper. It takes advantage of Digital Signal Processor（DSP）’s powerful data process ability to realize precise analysis and data processing. Moreover, the periphery circuit of this method is much simpler than above methods. Some particular functions such as frequency measurement and harmonic analysis could also be provided by using this method. The functions of local display and remote communication could be selected in accordance with requirement. The measuring result indicates that the ration error satisfies the national standard of 0.1 class transformer. And this method is quite general for its flexibility of the numbers of monitoring parameter in the high-voltage side and the bits of analog-to-digital convert. KEYWORDS: Electronic current transformer, DSP, Frequency measurement, Harmonic analysis INTRODUCTION As an important part of protecting and metering systems, the accuracy of current transformer is strongly relative with the security and reliability of power system. Conventional electromagnetic current transformers (CT), which are now frequently used in the power system, could ensure the accuracy and reliability required for metering and protection. But with the problem of difficult insulation and the effect of the saturation, the convent