| Transmission line microcomputer protection device is a kind of microcomputer system which provides relay protection to the transmission line,and it's becoming essentially protective device in the power system development.It's been comprised of four part:data processing unit,data acquisition unit,digital quantity input/output interface , and the commurication interface.Having consulted the domestic and foreign literature materials, and also analyzed the history,the present situation , the development tendency of the domestic and foreign microcomputers' relay protective technology, this paper put forwards a kind of microcomputer protection system based on DSP. Based on the wavelet analysis theory, this paper aims at fault data character extraction on transmission line, and dedicates on application of wavelet analysis of this field, exellent result is aquired in the experiment. It mainly includes the following sevral aspects:Firstly, this paper discusses the researching purpose of microcomputer protection .It introduces the overall plan of this system and gives detail introductions of data processing unit,data acquisition unit,digital quantity input/output interface and the commurication interface,then,it proposed a set of protection circuits design plan,and debugged it's serial port communication model.Sencondly,this paper also researches the wavelet analysis theory ,investigates frequency aliasing phenomenon,the reason why frequency aliasing phenomenon is easy to happen when wavelet is implied in the field of electrical power system microcomputer protective algorithm, and also the frequency bands where frequency aliasing phenomenon is easer to happen, then put forwards the improved Morlet wavelet analysis method which can effectively alleviates frequency aliasing phenomenon,and transplants the code to the TI's CCS platform to test it's validity.Finally,the algorithm is tested by MATLAB,the result is proved to be accurate.
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