Research On Microcomputer Measurement And Protection Device For Mid&Low-Voltage Transmission Line Based On Double CPU Platform

This thesis mainly discusses the research on the development of microcomputer measuring and protection device for Mid&Low-voltage transmission line based on double 80296SA platform. The work includes the analysis of protection theory, hardware system design of the device and the development of the software system.Firstly, it analyses the protection theory of Mid&Low-voltage transmission line based on the reference to a lot of articles and data, and promotes the stable and reliable judge based on three stage current protection.Secondly, it designs the hardware system of the device, and puts emphasis on the thorough research and design of the hardware platform of the modularized and united microcomputer measuring & protection device used in Mid&Low-voltage power system, from three points of protection section, supervision section and double ports RAM, including CPU unit, analog dada sampling unit, import and exit unit, man-computer interface unit, communication unit and power supply unit. The thesis detailedly analyzes the design and realization of each module.Thirdly, from two points of protection section and supervision section, it discusses the software modules of the device, including the main routine and the interrupt service routine. Based on the analysis of the requirement and characteristic of sampling AC electrical parameters, the advantages and disadvantages of many common algorithms and their application fields, it promotes a kind of Fourier transform algorithm considering both high calculating speed and precision.Aiming at the trend of fixing on the spot of microcomputer measuring and protection device in Integrated Automation Substation System, it emphasizes the importance of the the reliability of the design, and combining the shortage of the reliability of traditional device, it introduces the reliability of the design of microcomputer measuring and protection device including the screening capability of the device, the anti-interference methods from software and hardware, methods of improving the reliability of analog dada sampling system, and so on.In the end, it concludes the main work of this thesis and the work to be continued of it.