Research And Design On Novel Motor's Microprocessor-based Protection With Supervise And Control System

Motor is widely used in the industry and agriculture production, but the high fault ratio has caused enormous economic loss. Accordingly, based on the traditionally incomplete protective device, it is necessary to study and design a powerful and high reliable microprocessor-based protective device for motor.An introduction on the history, technical features and developing direction of microprocessor-based protection is presented through consulting a mass of references. Combined with the practical research item and based on theory with practice, a novel motor's microprocessor-based protective system is designed. In the system, DSP is used as Central Processor Unit and Fourier Algorithm is used as the core algorithm.Firstly, using symmetrical components method in this article, a theoretical analysis has been made on the motor running with the common faults. On the base of analyzing the protective principle of motor, a motor microprocessor-based protective scheme with high reliability and strong practicability is offered. Secondly, according to high speed and accuracy developing trend of the microprocessor protection and the characteristics of digital signal processor, a new motor's microprocessor-based protective device, which using double CPUs, is presented. As the main CPU, DSP completes such functions as sampling data, processing data and protection. 8051, as the secondly CPU, takes responsibility of conversational function between man and PC, such as dealing with keyboard, LCD and communication. With the excellence of parallel working and cooperating by dividing work, the dual CPU system can realize high accuracy of real-time measuring, as well as it can ensure the fast running ability, selectivity, sensitivity and reliability of relaying protect. Combined with data process algorithm and motor protection principle, the paper analyzed the hardware system in detail and designed the software system. Both of them used modularized structure designing method and can be transplanted easily.By debugging and analyzing the sample protection set, we validated the correctness of the system's hardware and software preliminarily. With static simulation test, we validated the reliability of the protection set preliminarily.