Research On Relay Protection Device Based On DSP For Distribution Power Line

With the rapid development of electric utility in our country,the user's requirement to the reliability of distribution network is higher and higher.Microcomputer relay protection device as the main automatic equipment for monitoring and protecting power system,how to improve its reliability and consummate its function is very important and emergent.After analyzing the development status of hardware,software and algorithm about microcomputer relay protection in detail,this paper do researches surrounding the distribution line microcomputer relay protection e,in which DSP is the core processor.TMS320LF2407 DSP chip from TI Co.is the core processor;the hardware platform mainly includes the development aim board research,peripheral circuit design,data acquirement circuit design and communication circuit design.14 bit AD converting chip AD7865 is extended for improving real-time sampling precision.RS232 interface and CAN field bus interface are extended for ensuring the data communication reliability.Different representative algorithms of the different models,such as sine wave function model,period function model and random model are analyzed and compared in detail,consequently draw a conclusion that the Fourier algorithm can acquire the higher precision and speed.To settle the problem of decaying periodic component in microcomputer protection,the computation error analysis of Fourier algorithm is deducted; the theory of improved parallel compensation Fourier algorithm is adapted.To eliminate the non-synchronous sampling phenomena aroused by the frequency fluctuation,the technology that adaptive adjusts sampling interval is used for regulation.Furthermore,the algorithm precision is validated.To improve the dependability of the software system and conveniency the user program maintenance and update,μC/OS-Ⅱreal-time operating system is import in the protection in this paper.On the base of analyzing theμC/OS-Ⅱoperating system core,its transplanting to TMS320LF2407 DSP chip is realized.The transplantling process is expatiated.and the testing code is finished to test.Finally,the user application program which include the selfcheck program,protection and judgement program,data real-time collection program,communication program,time program and three-section current protection program are completed.