Analysis And Design Of Low-voltage Intelligent Release Based On Devicenet,

Circuit breaker is used to connect or cutoff power line and protect and control many kinds of faulting, having the functions of overload protection, short-circuit protection, grounding protection and so on. Aimming at the defect of long-time lasting, low-precision and difficulty of adjusting of the traditional circuit breaker, the article provides the measuring ways and protection algorithm of the intelligence trip-relay, and make the design of hardware and software. The purpose is to realize the intellectual protection, remote control and concentrate management of circuit breaker.To satisfy the demand of selective protection of low-voltage power network and increasing the competition of new product, it is very important to design the intelligence trip relay with full protection ability and acceptable price. In this article, some practical problems for this design are contained, which start from the design of hardware and software. Firstly, the realizable ways of signal detection and sample, power circuit and the application of low-consumption model of MSP430 are discussed, by which the required function of current protection and voltage protection can be realized. Secondly, different protection algorithm based on micro-computer are discussed in this article, and from the virtues and defects of Fourier algorithm, an improved algorithm is put forward, and the importance of the improved algorithm is displaced. Thirdly, according to the national standard of GB/T18858 .3-2002, the principle of networklization of intelligence trip relay and how to realize it are mentioned. Lastly, using the current conditions, the test of precision is done. The experimental date present that the system is working well and can realize the real-time function of on-line detection.The experimental result shows that the design measures above can make the trip-relay realize its functions, and the practical results also proves it.