A Study On The Device For Motor Protection Based On DSP

As the power equipment widely used, the induction motor has been paid close attention to on its protection. In recent years, with the rapid development of computer technology, the microcomputer technology and digital signal processor (DSP) technology have got into the field of motor protection. Realizing multifunction and intelligence of motor protection with DSP technology has become developing direction in the future. The research on the protection device for motor based on DSP is the theme of this paper and the paper has developed a protection device for induction motor used in pumping station with such functions as protection, measurement and control. Firstly, the paper puts forward a protection project for induction motor based on digital signal processor according to a lot of articles and data. It analyses and summarizes the fault character and the protection theory of induction motor in briefly, configures the protection functions. Over current protection, negative current protection, zero sequence current protection, over time of start protection and low voltage protection is configured in the device. In the design of hardware platform, the paper adopts high speed float-point digital signal processor as the equipment's central processing unit (CPU), uses complex and programmable logic device (CPLD) instead of traditional and separate logic device, adopts LCD with large screen as the display platform and provides several communication modes. In the design of software system, it optimizes the algorithm making full use of the speediness of DSP, adopts modularized programming idea, subdivides large task into small function models, makes full use of characters of advanced C language's modularization and DSP assemble language's conciseness and high efficiency and programs to have realized all the protection functions. By testing, the software and hardware system designed can realize all the protection functions and can meet the needs of users. With the development of the computer technology and chip technology, the relay protection device based on the embedded real-time operating system will become the main developing direction of relay protection based on microcomputer for power system.